Rachel and Yoko collected buttons. Yoko gave 80% of her buttons to Rachel. As a result, Rachel's buttons increased by 40%. If Rachel had 42 buttons left, find the total number of buttons the two girls had at first.
| |
Comparing the change
in Yoko's buttons |
Yoko |
Rachel |
| Before |
5x1 =
5 u |
|
5x2 =
10 u |
| Change |
- 4x1 =
- 4 u |
- 2x2 =
- 4 u |
+ 2x2 =
+ 4 u |
| After |
1x1 =
1 u |
|
7x2 =
14 u |
80% =
80100 =
45 40% =
40100 =
25 The number of buttons that Rachel gave to Yoko is repeated. Make the number of buttons that Rachel gave to Yoko the same. LCM of 2 and 4 is 4.
Number of buttons that Rachel had in the end = 14 u
14 u = 42
1 u = 42 ÷ 14 = 3
Number of buttons that Yoko and Rachel had at first
= 5 u + 10 u
= 15 u
= 15 x 3
= 45
Answer(s): 45
