Question

Callum and Isobel have a total of 240 stamps.

The ratio of the number of Callum’s stamps to the number of Isabel’s stamps is 3:8.
Callum buys some stamps from Isabel.
The ratio of the number of Caullum’s stamps to the number of Isabel’s stamps is now 3:2
How many stamps does Callum buy from Isabel?
You must show all your working.
Please help.

Answer 1

Total stamps = 240

ratio= 3:8

3x + 8x = 240

11x = 240

x = 240/11 = 21.8

then, callum's stamps = 3x = 3 * 21.8 = 65.4

Isabel's stamps = 8x = 8 * 21.8 = 174.4

After buying the stamps,

ratio = 3:2

callum's stamps = 3x

Isabel's stamps = 2x

= 3x + 2x = 240

5 x = 240

x = 240/5 = 48

callum's stamps = 3x = 3 * 48 = 144

Isabel's stamps = 2x = 2 * 48 = 96

no. if stamps bought by calling = 144 - 65.4 = 78.6 stamps

hope it helps you