Xandra bought a total of 40 big and small jelly beans. Then she decided to exchange 75% of her big jelly beans for the small ones in the ratio of 3 : 7. After the exchange, she had 72 jelly beans. What percentage of the jelly beans she bought were small ones?
|
Big jelly beans |
Small jelly beans |
Total |
Before |
4 u |
? |
40 |
Change |
- 3 u |
|
|
Comparing big and small jelly beans at exchange |
- 3 u |
+ 7 u |
+ 32 |
After |
1 u |
? |
72 |
75% =
75100 =
34The number of big jelly beans that were exchanged for small jelly beans was repeated.
Number of extra jelly beans that Xandra received due to the exchange
= 7 u - 3 u
= 4 u
4 u = 72 - 40
4 u = 32
1 u = 32 ÷ 4 = 8
Number of small jelly beans at first
= 40 - 4 u
= 40 - 4 x 8
= 40 - 32
= 8
Percentage of the jelly beans Xandra bought that were small ones
=
840 x 100%
= 20%
Answer(s): 20%