Nora had 90% as many jelly beans as Esther. Nora gave away 20% of her jelly beans and Esther bought another 20 jelly beans. As a result, Nora now has 70% as many jelly beans as Esther. Find the number of jelly beans that Esther had at first.
| |
Nora |
Esther |
| Before |
9x7 |
10x7 |
| Change |
- 1.8x7 |
+ 20 |
| After |
7.2x7 |
10x7 + 20 |
Comparing Nora and
Esther in the end |
7x7.2 |
10x7.2 |
| |
Nora |
Esther |
| Before |
63 u |
70 u |
| Change |
- 12.6 u |
+ 20 |
After
|
50.4 u
|
70 u + 20 =
72 u |
90% =
90100 =
91020% x 9
=
20100 x 9
= 1.8
70% =
70100 =
710The number of jelly beans that Nora had in the end is repeated.
Make the number of jelly beans that Nora had in the end the same.
The number of jelly beans that Esther had in the end is repeated.
70 u + 20 = 72 u
72 u - 70 u = 20
2 u = 20
1 u = 20 ÷ 2 = 10
Number of jelly beans that Esther had at first
= 70 u
= 70 x 10
= 700
Answer: 700
