**Maths Questions for RRB NTPC Set-4 PDF**

Download RRB NTPC Maths Questions Set-4 PDF. Top 10 RRB NTPC questions based on asked questions in previous exam papers very important for the Railway NTPC exam.

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**Question 1: **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 2: **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 3: **If 15 boys earn Rs.900 in 5 days, how much will 20 boys earn in 7 days ?

a) Rs. 1980

b) Rs. 1820

c) Rs. 1780

d) Rs. 1680

**Question 4: **Given that log2 = 0.3 approx, one billion would be approximately

a) $2^{9}$

b) $2^{10}$

c) $2^{20}$

d) $2^{30}$

**Question 5: **Which of the following is the arithmetic mean of $ 2X^{2}-10, 30-X^{2} and -X^{2}+6X+10 $ ?

a) 3X+15

b) 6X+10

c) 2X+30

d) 2X+10

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**Question 6: **$ (1-\frac{1}{2}) (1-\frac{1}{3}) (1-\frac{1}{4}) …..(1-\frac{1}{40}) = ?$

a) $ \frac{1}{40} $

b) $ \frac{1}{20} $

c) Countless

d) Zero

**Question 7: **If one needs to score 34% to pass test, the pass marks out of 40 would be:

a) 13.2

b) 14.2

c) 13.6

d) 14.6

**Question 8: **A swimming pool is 20m long 15m wide and 3m deep. What will be the cost of repairing the floor and wall of the pool at the rate of Rs.25 per square metre ?

a) Rs. 17,250

b) Rs. 15,720

c) Rs . 12,750

d) None of the above

**Question 9: **A box contains coins (equal no. of every one) of rupee and half rupee, coins of 25 paise, 10 paise, 5 paise value, 2 paise value and one paise value. The total value of coins in the box is Rs. 1158. Find the number of coins of each value.

a) 500

b) 400

c) 700

d) 600

**Question 10: **A man sells his two cars at the same price. In one car he makes a profit or 10%. In other car he losses 10% over the cost price. His total gain or loss percent is

a) 1% loss

b) 1% gain

c) 2% loss

d) No loss no gain

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**Answers & Solutions:**

**1) 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

**2) 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

**3) Answer (D)**

Amount of money earned by a boy in a day = $\frac{900}{15*5}$ = Rs. 12

Hence, amount of money earned by 20 boys in 7 days = 20*7*12 = Rs. 1680

**4) Answer (D)**

1 billion = $10^9$

log (1 billion) = 9

log 2 = 0.3

$log_2$1billion = 30

=> 1 billion = $2^{30}$

**5) Answer (D)**

Mean = sum/3

= $ (2X^{2}-10 + 30-X^{2} -X^{2}+6X+10) $/3

= 2x + 10

**6) Answer (A)**

1 – 1/2 = 1/2

1 – 1/3 = 2/3

1 – 1/4 = 3/4

The denominator of the first term gets cancelled by the numerator of the second term and so on…

So, the final value = 1/40

**7) Answer (C)**

If one needs to score 34% to pass the test then the pass marks out of 40 would be 34 % of 40 i.e

0.34 x 40 = 13.6

Hence, option C is the correct answer.

**8) Answer (C)**

Total surface area to be painted = (15×20)+2(15×3)+2(20×3)= 510 $m^2$

Hence, the cost incurred = 510*25= Rs. 12750

Therefore, option C is the correct answer.

**9) Answer (D)**

Let the number of each coin be x

Total value of the box = x * 1 + x * .5 + x * .25 + x * .1 + x * .05 + x * .02 + x * .01 = x * (1.93)

But 1.93x = 1158

So, x = 1158/1.93 = 600 coins

**10) Answer (A)**

Let the cost price of the 2 cars be x and y.

The selling price of the cars = 1.1 x and .9y

but 1.1 x = .9 y

So, x = 9y/11 = .82 y

Total profit (or loss)= (1.1x + .9y – x – y)/(x+y) = (x/10 – y/10)/(x+ y) = (.82y/10 – y/10) / ( 1.82y) = 1% loss

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