Question

Izzati, Ai Ling, Rina and Susan share some stamps. Izzati and Ai Ling take 1/4 and 1/8 of the total number of stamps respectively. After that, Rina takes 7/10 of the remaining stamps. Eventually, all the remaining stamps are taken by Susan. If Susan gets 42 stamps, find the total number of stamps.​

Answer 1

224 stamps

Explanation:

Let total number of stamps = x

1/4 + 1/8 = (2 + 1) /8 = 3/8

3/8 of x = 3x/8

Remaining stamp = x - 3x/8 = (8x-3x)/8 = 5x/8

Rina = 7/10 of 5x /8

Rina = 7/10 * 5x /8 = 35x / 80

Remaining stamps = 5x/8 - 35x/80

Remaining stamps = (50x - 35x)/80 = 15x /80

15x / 80 = 42

15x = 80 * 42

15x = 3360

x = 3360 / 15

x = 224 stamps