Can someone help me with this problem, with proper steps?

Check out Mixture problems from quant concepts It’ll help

I think there are two ways to approach this problem.

(1) Set up mixture equation – 0.25A + 0.40B = 0.35(A+B)

Expand – 0.25A + 0.40B = 0.35A + 0.35B

Solve – 0.05B = 0.1A, thus A:B = 1:2

But the question asks for the proportion of A to the total mixture, thus the answer is 1:3 = 33.33% answer C.

(2) Do weighted average trick as suggested in Greg’s video

A% B%

25 40

35

5 10

Thus, A: B is 5:10 or 1:2 and A : Total is 1:3 answer C

This is hard to explain in text.