Question

The mean attendance of a class from Monday to Saturday was 34. If the mean attendance on Monday, Tuesday, Wednesday and Thursday was 33 and that on Thursday, Friday and Saturday was 35, then find the attendance on Thursday.

I'll mark as brilliant to the first one to answer it correctly with explanation ​

Answer 1

Let's denote the attendance on Monday, Tuesday, Wednesday, Thursday, Friday, and Saturday as M, T, W, Th, F, and S respectively. From the given information, we have the following equations:

(M + T + W + Th + F + S) / 6 = 34

(M + T + W + Th) / 4 = 33

(Th + F + S) / 3 = 35

Solving these equations, we get:

M + T + W + Th + F + S = 204

M + T + W + Th = 132

Th + F + S = 105

Subtracting the second equation from the first equation, we get:

F + S = 72

Subtracting this from the third equation, we get:

Th = 105 - 72 = 33

So the attendance on Thursday was 33.