Sign in
Please select an account to continue using cracku.in
↓ →
The average marks of the students in four sections A, B, C and D of a school is 60%. The average marks of the students of A, B, C and D individually are 45%, 50%, 72% and 80%, respectively. If the average marks of the students of sections A and B together is 48% and that of the students of B and C together is 60%, what is the ratio of the number of students in sections A and D?
Let $$a,b,c,d$$ be the number of students in A, B, C and D respectively
Given, average marks of the students in section A, B, C and D of the school = 60
Then $$\frac{45a + 50b + 72c + 80d}{a + b + c + d} = 60$$%
= $$45a + 50b + 72c + 80d = 60a + 60b + 60c + 60d$$
= $$12c + 20d = 15a + 10b$$..........(1)
Average marks of the students of sections A and B together is 48%,
= $$\frac{45a + 50b}{a + b} = 48$$%
= $$45a + 50b = 48a + 48b$$
= $$3a = 2b$$ (or) $$15a = 10b$$...............(2)
Average marks of the students of sections B and C together is 60%
= $$\frac{72c + 80d}{c + d} = 60$$%
= $$72c + 80d = 60c + 60d
= $$12c = 20d$$............(3)
Substitute equations (2) and (3) in equation (1)
$$\Rightarrow 20d + 20d = 15a + 15a$$
$$\Rightarrow 40d = 30a$$
$$\Rightarrow a : d = 4 : 3$$
Hence, option B is the correct answer.
Create a FREE account and get:
Book Free CAT Mentorship
Get personalized CAT strategy from a 99%iler
500+ students mentored
OTP Verification
Enter the 6-digit code sent to your phone
Booking Summary
Enter OTP
Didn't receive the OTP?
Start your IIM journey with the right preparation and crack CAT 2026.
Educational materials for CAT preparation