The ratio of silver to white stamps that Abi had was 5 : 4. The cost of each of the silver stamps was $3 and the cost of each of the white stamps was $4. Abi sold 20% of the silver stamps and the total cost of the unsold stamps was $196. How many white stamps did she have left?
| |
Silver stamps |
White stamps |
| Before |
5 u |
4 u |
| Change |
- 1 u |
|
| After |
4 u |
4 u |
Number of silver stamps sold
= 20% x 5 u
=
20100 x 5 u
= 1 u
| |
Silver stamps |
White stamps |
Total |
| Number |
4 u |
4 u |
|
| Value |
$3 |
$4 |
|
| Total value |
12 u |
16 u |
$196 |
Total cost of unsold stamps
= 12 u + 16 u
= 28 u
28 u = 196
1 u = 196 ÷ 28 = 7
Number of white stamps that Abi had left
= 16 u
= 16 x 7
= 112
Answer(s): 112
