Betty and Elyse collected coins. Betty gave 10% of her coins to Elyse. As a result, Elyse's coins increased by 80%. If Betty had 252 coins left, find the total number of coins the two girls had at first.
| |
Betty |
Elyse |
Comparing the change
in Elyse's coins |
| Before |
10x4 =
40 u |
|
5x1 =
5 u |
| Change |
- 1x4 =
- 4 u |
+ 1x4 =
+ 4 u |
+ 4x1 =
+ 4 u |
| After |
9x4 =
36 u |
|
9x1 =
9 u |
10% =
10100 =
110 80% =
80100 =
45 The number of coins that Betty gave to Elyse is repeated. Make the number of coins that Betty gave to Elyse the same. LCM of 1 and 4 is 4.
Number of coins that Betty had in the end = 36 u
36 u = 252
1 u = 252 ÷ 36 = 7
Number of coins that Betty and Elyse had at first
= 40 u + 5 u
= 45 u
= 45 x 7
= 315
Answer(s): 315
