# The average marks of sam decreased by 1, when he replaced the subject

| The average marks of sam decreased by 1, when he replaced the subject in which he has scored 40 by the other two subjects in which he scored 23 and 25 marks respectively. Later he has also included 57 marks of computer science, then the average marks increased by 2. How many subjects were there initially?

A. 6

B. 15

C. 12

D. 14

### Right Answer is: B

#### SOLUTION

Let the number of subjects be n and average marks be x, then the total marks = nx

Again

(since, x-1+2 = x + 1)

Now on solving the equations, we get n = 15 and x = 24

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The average marks of sam decreased by 1, when he replaced the subject