Tammy bought a total of 80 big and small sweets. Then she decided to exchange 25% of her big sweets for the small ones in the ratio of 1 : 6. After the exchange, she had 90 sweets. What percentage of the sweets she bought were small ones?
| |
Big sweets |
Small sweets |
Total |
| Before |
4 u |
? |
80 |
| Change |
- 1 u |
|
|
Comparing big and
small sweets at exchange |
- 1 u |
+ 6 u |
+ 10 |
| After |
3 u |
? |
90 |
25% =
25100 =
14The number of big sweets that were exchanged for small sweets was repeated.
Number of extra sweets that Tammy received due to the exchange
= 6 u - 1 u
= 5 u
5 u = 90 - 80
5 u = 10
1 u = 10 ÷ 5 = 2
Number of small sweets at first
= 80 - 4 u
= 80 - 4 x 2
= 80 - 8
= 72
Percentage of the sweets Tammy bought that were small ones
=
7280 x 100%
= 90%
Answer(s): 90%
