The average of marks obtained by SI and S2 is 35 more than the average of marks obtained by S2 and S3. If the marks obtained by S3 is 75, then what are the marks obtained by 51?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 145.
( M1) be the marks obtained by SI,
( M2) be the marks obtained by S2,
( M3 = 75) be the marks obtained by S3.
The average of the marks obtained by SI and S2 is:
⇒ M1 + M2 / 2 ......(1)
The average of the marks obtained by S2 and S3 is:
⇒ M2 + M3 / 2 = M2 + 75 / 2......(2)
equation (1) and (2):
⇒ M1 + M2 / 2 = M2 + 75 / 2 + 35
⇒ M1 + M2 = M2 + 75 + 70
⇒ M1 + M2 = M2 + 145
⇒ M1 = 145