Will's and Risa's monthly allowances were the same at first. Will's allowance increased by 20% while Risa's decreased by 15%. Given that Will's allowance would decrease by another 25% if he had received $726 less from his parents, find the difference in the children's monthly allowances.
| |
Will |
Risa |
| Before |
1 u |
1 u |
| Change 1 |
+ 0.2 u |
- 0.15 u |
| After 1 |
1.2 u |
0.85 u |
| Change 2 |
- 0.3 u |
No change |
| After 2 |
0.9 u |
0.85 u |
Increase in Will's allowance
= 20% x 1 u
=
20100 x 1 u
= 0.2 u
Decrease in Risa's allowance
= 15% x 1 u
=
15100 x 1 u
= 0.15 u
Decrease in Will's allowance if he had received $726 less from his parents
= 25% x 1.2 u
=
25100 x 1.2 u
= 0.3 u
0.3 u = 726
1 u = 726 ÷ 0.3 = 2420
Difference in the allowance between Will and Risa
= 1.2 u - 0.85 u
= 0.35 u
= 0.35 x 2420
= $847
Answer(s): $847
