Risa had $185 less than Mary. Mary spent
25 of her money and Risa spent
45 of her money. In the end, Mary had 4 times as much as Risa. Find the amount of money Mary had at first.
| |
Mary |
Risa |
Comparing Mary
and Risa at first |
$185 more |
|
| Before |
5x4 =
20 u |
5x3 =
15 u |
| Change |
- 2x4 =
- 8 u |
- 4x3 =
- 12 u |
| After |
3x4 =
12 u |
1x3 =
3 u |
Comparing Mary
and Risa in the end |
4x3 =
12 u |
1x3 =
3 u |
The amount that Mary had in the end is repeated. Make the amount that Mary had in the end the same. LCM of 4 and 3 is 12.
Amount that Risa had less than Mary
= 20 u - 15 u
= 5 u
5 u = 185
1 u = 185 ÷ 5 = 37
Amount that Mary had at first
= 20 u
= 20 x 37
= $740
Answer(s): $740
