Abi bought a total of 240 big and small sweets. Then she decided to exchange 80% of her big sweets for the small ones in the ratio of 4 : 7. After the exchange, she had 276 sweets. What percentage of the sweets she bought were small ones?
| |
Big sweets |
Small sweets |
Total |
| Before |
5 u |
? |
240 |
| Change |
- 4 u |
|
|
Comparing big and
small sweets at exchange |
- 4 u |
+ 7 u |
+ 36 |
| After |
1 u |
? |
276 |
80% =
80100 =
45The number of big sweets that were exchanged for small sweets was repeated.
Number of extra sweets that Abi received due to the exchange
= 7 u - 4 u
= 3 u
3 u = 276 - 240
3 u = 36
1 u = 36 ÷ 3 = 12
Number of small sweets at first
= 240 - 5 u
= 240 - 5 x 12
= 240 - 60
= 180
Percentage of the sweets Abi bought that were small ones
=
180240 x 100%
= 75%
Answer(s): 75%
