Gwen had 90% as many chocolate bars as Rachel. Gwen gave away 20% of her chocolate bars and Rachel bought another 10 chocolate bars. As a result, Gwen now has 70% as many chocolate bars as Rachel. Find the number of chocolate bars that Gwen had in the end.
| |
Gwen |
Rachel |
| Before |
9x7 |
10x7 |
| Change |
- 1.8x7 |
+ 10 |
| After |
7.2x7 |
10x7 + 10 |
Comparing Gwen and
Rachel in the end |
7x7.2 |
10x7.2 |
| |
Gwen |
Rachel |
| Before |
63 u |
70 u |
| Change |
- 12.6 u |
+ 10 |
After
|
50.4 u
|
70 u + 10 =
72 u |
90% =
90100 =
91020% x 9
=
20100 x 9
= 1.8
70% =
70100 =
710The number of chocolate bars that Gwen had in the end is repeated.
Make the number of chocolate bars that Gwen had in the end the same.
The number of chocolate bars that Rachel had in the end is repeated.
70 u + 10 = 72 u
72 u - 70 u = 10
2 u = 10
1 u = 10 ÷ 2 = 5
Number of chocolate bars that Gwen had in the end
= 50.4 u
= 50.4 x 5
= 252
Answer: 252
