Erika and Diana collected buttons. Erika gave 20% of her buttons to Diana. As a result, Diana's buttons increased by 70%. If Erika had 252 buttons left, find the total number of buttons the two girls had at first.
| |
Erika |
Diana |
Comparing the change
in Diana's buttons |
| Before |
5x7 =
35 u |
|
10x1 =
10 u |
| Change |
- 1x7 =
- 7 u |
+ 1x7 =
+ 7 u |
+ 7x1 =
+ 7 u |
| After |
4x7 =
28 u |
|
17x1 =
17 u |
20% =
20100 =
15 70% =
70100 =
710 The number of buttons that Erika gave to Diana is repeated. Make the number of buttons that Erika gave to Diana the same. LCM of 1 and 7 is 7.
Number of buttons that Erika had in the end = 28 u
28 u = 252
1 u = 252 ÷ 28 = 9
Number of buttons that Erika and Diana had at first
= 35 u + 10 u
= 45 u
= 45 x 9
= 405
Answer(s): 405
