Mary bought a total of 80 big and small jelly beans. Then she decided to exchange 25% of her big jelly beans for the small ones in the ratio of 1 : 5. After the exchange, she had 100 jelly beans. What percentage of the jelly beans she bought were small ones?
| |
Big jelly beans |
Small jelly beans |
Total |
| Before |
4 u |
? |
80 |
| Change |
- 1 u |
|
|
Comparing big and
small jelly beans at exchange |
- 1 u |
+ 5 u |
+ 20 |
| After |
3 u |
? |
100 |
25% =
25100 =
14The number of big jelly beans that were exchanged for small jelly beans was repeated.
Number of extra jelly beans that Mary received due to the exchange
= 5 u - 1 u
= 4 u
4 u = 100 - 80
4 u = 20
1 u = 20 ÷ 4 = 5
Number of small jelly beans at first
= 80 - 4 u
= 80 - 4 x 5
= 80 - 20
= 60
Percentage of the jelly beans Mary bought that were small ones
=
6080 x 100%
= 75%
Answer(s): 75%
