Abi had 90% as many jelly beans as Barbara. Abi gave away 10% of her jelly beans and Barbara bought another 220 jelly beans. As a result, Abi now has 70% as many jelly beans as Barbara. Find the number of jelly beans that Barbara had at first.
|
Abi |
Barbara |
Before |
9x7 |
10x7 |
Change |
- 0.9x7 |
+ 220 |
After |
8.1x7 |
10x7 + 220 |
Comparing Abi and Barbara in the end |
7x8.1 |
10x8.1 |
|
Abi |
Barbara |
Before |
63 u |
70 u |
Change |
- 6.3 u |
+ 220 |
After
|
56.7 u
|
70 u + 220 = 81 u |
90% =
90100 =
91010% x 9
=
10100 x 9
= 0.9
70% =
70100 =
710The number of jelly beans that Abi had in the end is repeated.
Make the number of jelly beans that Abi had in the end the same.
The number of jelly beans that Barbara had in the end is repeated.
70 u + 220 = 81 u
81 u - 70 u = 220
11 u = 220
1 u = 220 ÷ 11 = 20
Number of jelly beans that Barbara had at first
= 70 u
= 70 x 20
= 1400
Answer: 1400