Irene had 90% as many chocolate bars as Cathy. Irene gave away 20% of her chocolate bars and Cathy bought another 60 chocolate bars. As a result, Irene now has 60% as many chocolate bars as Cathy. Find the number of chocolate bars that Irene had in the end.
| |
Irene |
Cathy |
| Before |
9x3 |
10x3 |
| Change |
- 1.8x3 |
+ 60 |
| After |
7.2x3 |
10x3 + 60 |
Comparing Irene and
Cathy in the end |
3x7.2 |
5x7.2 |
| |
Irene |
Cathy |
| Before |
27 u |
30 u |
| Change |
- 5.4 u |
+ 60 |
After
|
21.6 u
|
30 u + 60 =
36 u |
90% =
90100 =
91020% x 9
=
20100 x 9
= 1.8
60% =
60100 =
35The number of chocolate bars that Irene had in the end is repeated.
Make the number of chocolate bars that Irene had in the end the same.
The number of chocolate bars that Cathy had in the end is repeated.
30 u + 60 = 36 u
36 u - 30 u = 60
6 u = 60
1 u = 60 ÷ 6 = 10
Number of chocolate bars that Irene had in the end
= 21.6 u
= 21.6 x 10
= 216
Answer: 216
