Hazel had 90% as many chocolate bars as Min. Hazel gave away 20% of her chocolate bars and Min bought another 20 chocolate bars. As a result, Hazel now has 70% as many chocolate bars as Min. Find the number of chocolate bars that Min had at first.
| |
Hazel |
Min |
| Before |
9x7 |
10x7 |
| Change |
- 1.8x7 |
+ 20 |
| After |
7.2x7 |
10x7 + 20 |
Comparing Hazel and
Min in the end |
7x7.2 |
10x7.2 |
| |
Hazel |
Min |
| 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 chocolate bars that Hazel had in the end is repeated.
Make the number of chocolate bars that Hazel had in the end the same.
The number of chocolate bars that Min 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 chocolate bars that Min had at first
= 70 u
= 70 x 10
= 700
Answer: 700
