Wendy bought a total of 60 big and small jelly beans. Then she decided to exchange 50% of her big jelly beans for the small ones in the ratio of 1 : 4. After the exchange, she had 78 jelly beans. What percentage of the jelly beans she bought were small ones?
| |
Big jelly beans |
Small jelly beans |
Total |
| Before |
2 u |
? |
60 |
| Change |
- 1 u |
|
|
Comparing big and
small jelly beans at exchange |
- 1 u |
+ 4 u |
+ 18 |
| After |
1 u |
? |
78 |
50% =
50100 =
12The number of big jelly beans that were exchanged for small jelly beans was repeated.
Number of extra jelly beans that Wendy received due to the exchange
= 4 u - 1 u
= 3 u
3 u = 78 - 60
3 u = 18
1 u = 18 ÷ 3 = 6
Number of small jelly beans at first
= 60 - 2 u
= 60 - 2 x 6
= 60 - 12
= 48
Percentage of the jelly beans Wendy bought that were small ones
=
4860 x 100%
= 80%
Answer(s): 80%
