Irene had 90% as many chocolate bars as Hilda. Irene gave away 10% of her chocolate bars and Hilda bought another 210 chocolate bars. As a result, Irene now has 60% as many chocolate bars as Hilda. Find the number of chocolate bars that Irene had in the end.
| |
Irene |
Hilda |
| Before |
9x3 |
10x3 |
| Change |
- 0.9x3 |
+ 210 |
| After |
8.1x3 |
10x3 + 210 |
Comparing Irene and
Hilda in the end |
3x8.1 |
5x8.1 |
| |
Irene |
Hilda |
| Before |
27 u |
30 u |
| Change |
- 2.7 u |
+ 210 |
After
|
24.3 u
|
30 u + 210 =
40.5 u |
90% =
90100 =
91010% x 9
=
10100 x 9
= 0.9
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 Hilda had in the end is repeated.
30 u + 210 = 40.5 u
40.5 u - 30 u = 210
10.5 u = 210
1 u = 210 ÷ 10.5 = 20
Number of chocolate bars that Irene had in the end
= 24.3 u
= 24.3 x 20
= 486
Answer: 486
