Joelle bought a total of 55 big and small chocolate bars. Then she decided to exchange 25% of her big chocolate bars for the small ones in the ratio of 1 : 3. After the exchange, she had 77 chocolate bars. What percentage of the chocolate bars she bought were small ones?
|
Big chocolate bars |
Small chocolate bars |
Total |
Before |
4 u |
? |
55 |
Change |
- 1 u |
|
|
Comparing big and small chocolate bars at exchange |
- 1 u |
+ 3 u |
+ 22 |
After |
3 u |
? |
77 |
25% =
25100 =
14The number of big chocolate bars that were exchanged for small chocolate bars was repeated.
Number of extra chocolate bars that Joelle received due to the exchange
= 3 u - 1 u
= 2 u
2 u = 77 - 55
2 u = 22
1 u = 22 ÷ 2 = 11
Number of small chocolate bars at first
= 55 - 4 u
= 55 - 4 x 11
= 55 - 44
= 11
Percentage of the chocolate bars Joelle bought that were small ones
=
1155 x 100%
= 20%
Answer(s): 20%