Risa had $425 less than Bobby. Bobby spent 0.6 of his money and Risa spent 0.4 of her money. In the end, Bobby and Risa had the same amount of money left. Find the amount of money Risa had at first.
| |
Risa |
Bobby |
Difference |
| Before |
10 u |
15 u |
5 u |
| Change |
- 2 u |
- 3 u |
|
| After |
6 u |
6 u |
|
0.6 =
35 Fraction of Bobby's amount left
= 1 -
35 =
25 0.4 =
25 Fraction of Risa's amount left
= 1 -
25 =
35 The amount that Bobby and Risa each had in the end is the same. Make the numerators the same. LCM of 2 and 3 is 6.
25 of Bobby's amount =
35 of Risa's amount
615 of Bobby's amount =
610 of Risa's amount
Amount that Risa had less than Bobby
= 15 u - 10 u
= 5 u
5 u = 425
1 u = 425 ÷ 5 = 85
Amount that Risa had at first
= 10 u
= 10 x 85
= $850
Answer(s): $850
