Question

In a particular test, the marks scored by 4 candidates - A, B, C and D are as follows:

• Marks obtained by A and B add to 100;
• Marks obtained by C and D add up to those scored by A;
• B scores 4 times of D;
• D scores 10 marks less than C.
• The marks obtained by C will be

1. 30
2. 15
3. 20
4. 25

Answer 1

Correct Answer - Option 4 : 25

According to the given condition

1) Marks obtained by A and B add to 100

A + B = 100 ------ (1)

2) Marks obtained by C and D add up to those scored by A

C + D = A ------- (2)

3) B scores 4 times of D

B = 4 D -------- (3)

4) D scores 10 marks less than C

D = C - 10 ----- (4)

Add equation (1) and (2)

A + B + C + D = 100 + A

⇒ B + C + D = 100

Put the value of B from equation (3)

4 D + C + D = 100 

Put the value of D from equation (4)

5 (C - 10) + C = 100

⇒ 5 C - 50 + C = 100

⇒ 6 C = 150

⇒ C = 25

Hence, "25" is the correct answer.