Track / Stage 4 / 315 of 340 #575 of 1964

Problem 575

AMC 12 late, AIME early

Algebra Difficulty 5.0 Multiple choice

The average of four test marks was 60 . The first three marks were 30,55 and 65 . What was the fourth mark?

Pick one

Official solution

The average of four test marks was 60 . The first three marks were 30,55 and 65 . What was the fourth mark?
(A) 40
(B) 55
(C) 60
(D) 70
(E) 90

## Solution

The total number of marks scored on the four tests was $4 \times 60$ or 240 . The total number of marks scored on the first three tests was 150. The fourth mark was $240-150=90$ . ANSWER: (E)

Source: NuminaMath-1.5, licensed Apache-2.0. Statement and solution reproduced as published; topic, difficulty and ordering added by this site.