Jane bought a total of 75 big and small chocolate bars. Then she decided to exchange 60% of her big chocolate bars for the small ones in the ratio of 3 : 5. After the exchange, she had 81 chocolate bars. What percentage of the chocolate bars she bought were small ones?
| |
Big chocolate bars |
Small chocolate bars |
Total |
| Before |
5 u |
? |
75 |
| Change |
- 3 u |
|
|
Comparing big and
small chocolate bars at exchange |
- 3 u |
+ 5 u |
+ 6 |
| After |
2 u |
? |
81 |
60% =
60100 =
35The number of big chocolate bars that were exchanged for small chocolate bars was repeated.
Number of extra chocolate bars that Jane received due to the exchange
= 5 u - 3 u
= 2 u
2 u = 81 - 75
2 u = 6
1 u = 6 ÷ 2 = 3
Number of small chocolate bars at first
= 75 - 5 u
= 75 - 5 x 3
= 75 - 15
= 60
Percentage of the chocolate bars Jane bought that were small ones
=
6075 x 100%
= 80%
Answer(s): 80%
