Hilda bought a total of 400 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 : 6. After the exchange, she had 450 chocolate bars. What percentage of the chocolate bars she bought were small ones?
|
Big chocolate bars |
Small chocolate bars |
Total |
Before |
4 u |
? |
400 |
Change |
- 1 u |
|
|
Comparing big and small chocolate bars at exchange |
- 1 u |
+ 6 u |
+ 50 |
After |
3 u |
? |
450 |
25% =
25100 =
14The number of big chocolate bars that were exchanged for small chocolate bars was repeated.
Number of extra chocolate bars that Hilda received due to the exchange
= 6 u - 1 u
= 5 u
5 u = 450 - 400
5 u = 50
1 u = 50 ÷ 5 = 10
Number of small chocolate bars at first
= 400 - 4 u
= 400 - 4 x 10
= 400 - 40
= 360
Percentage of the chocolate bars Hilda bought that were small ones
=
360400 x 100%
= 90%
Answer(s): 90%