Yoko had 90% as many sweets as Mary. Yoko gave away 20% of her sweets and Mary bought another 20 sweets. As a result, Yoko now has 70% as many sweets as Mary. Find the number of sweets that Yoko had in the end.
| |
Yoko |
Mary |
| Before |
9x7 |
10x7 |
| Change |
- 1.8x7 |
+ 20 |
| After |
7.2x7 |
10x7 + 20 |
Comparing Yoko and
Mary in the end |
7x7.2 |
10x7.2 |
| |
Yoko |
Mary |
| 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 sweets that Yoko had in the end is repeated.
Make the number of sweets that Yoko had in the end the same.
The number of sweets that Mary 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 sweets that Yoko had in the end
= 50.4 u
= 50.4 x 10
= 504
Answer: 504
