Important Questions On Ratio and Proportions for RRB NTPC Exam

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Important Questions On Ratio and Proportions for RRB NTPC Exam
Important Questions On Ratio and Proportions for RRB NTPC Exam.

Ratio and Proportion Questions for RRB NTPC Exam.

Download the most important questions on Ratio and Proportions for RRB NTPC Exam. Most important  Ratio & Proportions questions based on asked questions in previous exam papers for RRB NTPC. These questions are also helpful for all other competitive exams.

Download Important Questions On Ratio and Proportions for RRB NTPC Exam.

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Question 1: 35 is the average marks obtained by 120 students. The average marks of successful candidates was 39 and that of unsuccessful candidates was 15. What is the number of successful candidates in that examination ?

a) 100

b) 110

c) 120

d) 80

Question 2: A number of two digits is equal to ‘k’ times to the sum of these digits. If the places of the digits are mutually exchanged, the new formed number is equal to the sum of these digits multiplied by which one of the following options ?

a) 9 + k

b) 10 + k

c) 11 – k

d) k – 1

Question 3: 45 is the average marks obtained by 30 students of a class. On checking, two errors were identified. On correction, one student obtained 45 more marks while other obtained 15 less marks. What is the average of corrected marks ?

a) 45

b) 44

c) 47

d) 46

Question 4: 5 years ago, average age of P and Q was 15 years. At present, average age of P, Q and R is 20 years. What will be the average age after 10 years ?

a) 35 years

b) 40 years

c) 30 years

d) 50 years

Question 5: The ratio of the present age of a man and his wife is 4:3 and 4 years hence the ratio of their ages will be 9:7 If the ratio of their ages at the time of their marriage was 13:9, how many years ago were they married ?

a) 4

b) 8

c) 6

d) 9

Question 6: The average height of 35 students in a class is 4’2”. Three students of average height moved to new section while 6 students of total height 33’4” joined the class The average height of the student in the class is now

a) 4’6”

b) 5’

c) 4’4”

d) 4’8”

Question 7: The ratio of the ages of X and Y three years ago was 4:5 and that after three years will be 5:6. Then the sum of the ages of X and Y is

a) 60 years

b) 64 years

c) 72 years

d) 58 years

Question 8: The volumes of three kinds of materials are in the ratio 3:4:7 and the weights of equal volumes of the three materials are in the ratio 5:2:6 If they are mixed to form a material of 65 kg then the weight of the 2nd material in the mixture is

a) 8 kg

b) 23 kg

c) 15 kg

d) 42 kg

Question 9: A man worked 14 hours a day for the first 2 days, 12 hours a day for the next 3 days but did not work on the sixth day. Then on the average how much did he work in the first six days ?

a) 10 hours 4 minutes

b) 9 hours 40 minutes

c) 10 hours 40 minutes

d) 15 hours 40 minutes

Question 10: A sum of Rs. 625 is made up of 80 currency notes which are either Rs. 10 or Rs. 5 denomination. The number of Rs. 10 notes are———

a) 35

b) 45

c) 40

d) 30

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Question 11: The average expenditure of a man for the first five months is Rs. 1200 and for the next seven months is Rs. 1300. Find his monthly average income if he saves Rs. 2900 during the year ?

a) Rs. 1500

b) Rs. 1475

c) Rs. 1450

d) Rs. 1425

Question 12: The average temperature for Monday, Tuesday and Wednesday was 40C. The average for Tuesday, Wednesday and Thursday was 41 C. If on Thursday temperature is 45C, what was it on Monday ?

a) 40C

b) 41C

c) 42C

d) 43.5C

Question 13: Of the three numbers, second is twice the first and is also thrice the third. If the average of the three numbers is 44, the largest number is-

a) 24

b) 72

c) 36

d) 108

Question 14: Of the three numbers whose average is 60, the first is one fourth of the sum of the others. The first number is–

a) 30

b) 36

c) 42

d) 45

Question 15: The average age of a family of 5 members is 24 years. If the age of the youngest member be 6 years, find the average age of the family at the birth of the youngest member-

a) $ 23 \frac{1}{2} $

b) $20$ years

c) $ 22 \frac{1}{2} $

d) $18$ years

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Question 16: 9 men went to a hotel 8 of them spent Rs. 30 each over their meals and the 9th person spent Rs. 20 more than the average expenditure of all the nine. The total money spent by them is–

a) Rs. 292.50

b) Rs. 272.50

c) Rs. 312.50

d) Rs. 325.50

Question 17: In a circle team of eleven players, one player weighing 42 kg, is injured and his place is taken by another player. If the average weight of the team is increased by 100 grams as a result of this, then the weight of the new player is–

a) 43.1 kg

b) 43.01 kg

c) 43.50 kg

d) 42.9 kg

Question 18: The average age of 8 persons in a committee is increased by two years when two men whose ages are 35 years and 45 years are replaced by two women. The average age of two women is (in yrs)–

a) 40

b) 42

c) 48

d) 45

Question 19: One-fourth of a certain journey was covered at an average speed of 45 km/hour, one-third at the speed of 48 km/hour and the remaining journey at the speed of 50 km/hour. The average age speed of the whole journey in km/hour is—

a) 54

b) 51

c) 48

d) 46

Question 20: Visitors to a show were charged Rs. 150.00 each on the first day, Rs. 75.00 on the second day and Rs. 25.00 on the third day and the total attendance on the three days were in the ratio 2 : 5 : 13. The average charge per person for the whole show is–

a) Rs. 75.00

b) Rs. 60.00

c) Rs. 50.00

d) Rs. 55.00

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Answers & Solutions:

1) Answer (A)

Let there be x successful candidates in the exam.

Unsuccessful candidates = 120 – x

Total score = 35 x 120

Total score is also equal to x * 39 + (120 – x) * 15

So, x = (35 * 120 – 120 * 15)/ 24 = 120 * 20 / 24 = 100

2) Answer (C)

Let the number be xy. So 10 x +y = k (x + y)

11 – k = 11- $ \frac{10x+y}{x+y}$ = $\frac{11x + 11y – 10x – y}{x+y}$

= $ \frac {10y + x}{x+y}$ which is inverse of the number divided by the sum of the digits.

Hence the required factor is 11 – k

3) Answer (D)

On correction, total increase in marks = 45 – 15 = 30 marks.

Number of students = 30

So, increase in the average = 30/30 = 1 mark.

4) Answer (C)

The average age increases with age. So, after 10 years, the average age is 20 + 10 = 30 years.

5) Answer (C)

Let the ages today be 4x and 3x. Ages four years from now are 4x + 4 and 3x + 4

But 4x+4:3x+4 = 9:7

So, x = 8

So, their current ages = 32 and 24

Let them be married for x years

Age at marriage = 32 – x and 24 – x

But 32 – x : 24 – x = 13: 9

So  x = 6 years.

6) Answer (C)

After the students left, there will be 32 students with the same average height. 4 ft and 2 inches

Total height = 32 x 4.17 = 133.44

Total height of 6 students is 33 ft and 4 inches.  = 33.33

New total height = 133.44 + 33.33 = 166.77

New average height = 166.77/ 38 = 4 feet 4 inches

7) Answer (A)

Let the ages of X and Y 3 years ago be 4x and 5x. Ages 6 years from then are 4x+6 and 5x+6

But 4x+6:5x+6 = 5:6

Solving we get the answer as x = 6

Sum of today’s ages = 4x + 5x + 6 = 9x + 6 = 60 years

8) Answer (A)

Let the volumes of the 3 be: 3v, 4v and 7v

Densities of the three are 5d, 2d and 6d

So, the weights are 15dv + 8 dv + 42 dv = 65 dv

But that is 65 kilograms.

The second one’s weight is 8 dv = 8 kgs

9) Answer (C)

Total number of hours worked by the man = 14 x 2 + 12 x 3 = 64 hours

So, the average in 6 days = 64/6 = 10 hours and 40 mins

10) Answer (B)

Let there be x 10 rupee notes. So the number of 5 rupee notes = 80 – x

So, total value of the money = 10x + (80- x)*5

= 10x + 400 – 5x = 400 + 5x

But 400 + 5x = 625

so x = 225/5 = 45

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11) Answer (A)

Let his monthly salary be x rupees.

So, 5 (x – 1200) + 7 (x-1300) = 2900

12x – 6000 – 9100 = 2900

So, x = 18000/12 = 1500

12) Answer (C)

Total temperature for Monday, Tuesday, Wednesday and Thursday = 40 x 3 + 45 = 165 C

Total for Tuesday, Wednesday and Thursday = 41 x 3 = 123 C

So,

Temperature for Monday = 165 – 123 = 42 C

13) Answer (B)

Let the first number be 3x. Second number is 6x. Third number is 2x.

So average = (2x + 3x + 6x)/3 = 11x/3

But 11x/3 = 44

So, x = 12

6x = 72

14) Answer (B)

The average of the three numbers is 60

The first number is one fourths of the sum of the others.

or 4p = q + r

$ \frac {p + q + r}{3}$ = 60

So, 5p/3 = 60

p = 180/5 = 36

15) Answer (C)

The total age of the 5 members = 120 years.

Age of the youngest member is 6 years.

Total age of the rest of the group = 114 years.

Average age = 114/4

Average age 6 years ago = 114/4 – 6 = 28.5 – 6 = 22.5 years.

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16) Answer (A)

Let the ninth person’s expenses be x rupees.

Total expense by the group = x + 240

Average = (x+ 240)/9

But the average is 20 less than x

(x+240)/9 + 20 = x

x + 240 + 180 = 9x

8x = 420

x = 52.5

17) Answer (A)

Let the weight of the new player be x kgs.

Total weight as a result of his inclusion = TW – 42 + x

Average weight = (TW – 42 + x)/11

But average weight before = TW/11

(TW – 42 + x)/11 – TW/11 = .1

x – 42 = 1.1

So, x = 43.1 kgs

18) Answer (C)

Let the average age of the women be A years.

Total of their ages = 2A

Total of the eight persons = ET

When replaced (ET – 80 + 2A)/8 = ET/8 + 2

2A – 80 = 16

A = 96/2 = 48

19) Answer (C)

Let the total distance be 1200 kms

Time taken for first one fourth = 300/ 45 = 20/3 = 6.67

Next one third time = 400/ 48 = 25/3 = 8.33

Remaining = 500/50 = 10

Average speed = total distance / total time = 1200/25 = 48 kmph

20) Answer (C)

Let the total visitors be 20. Total revenue = 2 x 150 + 5 x 75 + 13 x 25 = 300 + 375 + 325

= 1000

Average ticket price = Total revenue / total visitors = 1000/ 20 = 50

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