Zoe bought a total of 220 big and small sweets. Then she decided to exchange 20% of her big sweets for the small ones in the ratio of 1 : 6. After the exchange, she had 275 sweets. What percentage of the sweets she bought were small ones?
| |
Big sweets |
Small sweets |
Total |
| Before |
5 u |
? |
220 |
| Change |
- 1 u |
|
|
Comparing big and
small sweets at exchange |
- 1 u |
+ 6 u |
+ 55 |
| After |
4 u |
? |
275 |
20% =
20100 =
15The number of big sweets that were exchanged for small sweets was repeated.
Number of extra sweets that Zoe received due to the exchange
= 6 u - 1 u
= 5 u
5 u = 275 - 220
5 u = 55
1 u = 55 ÷ 5 = 11
Number of small sweets at first
= 220 - 5 u
= 220 - 5 x 11
= 220 - 55
= 165
Percentage of the sweets Zoe bought that were small ones
=
165220 x 100%
= 75%
Answer(s): 75%
