Mary had $75 less than Risa. Risa spent 0.2 of her money and Mary spent 10% of her money. In the end, Risa and Mary had the same amount of money left. Find the amount of money that Risa had at first.
| |
Mary |
Risa |
Comparing Risa
and Mary at first |
|
75 more |
| Before |
10x4 =
40 u |
5x9 =
45 u |
| Change |
- 1x4 =
- 4 u |
- 1x9 =
- 9 u |
| After |
9x4 =
36 u |
4x9 =
36 u |
0.2 =
210 =
15 10% =
10100 =
110 Mary and Risa had the same amount of money in the end. Make the amount that each had in the end the same. LCM of 4 and 9 is 36.
Amount that Mary had less than Risa at first
= 45 u - 40 u
= 5 u
5 u = 75
1 u = 75 ÷ 5 = 15
Amount that Risa had at first
= 45 u
= 45 x 15
= $675
Answer(s): $675
