Tom's and Fanny's monthly allowances were the same at first. Tom's allowance increased by 25% while Fanny's decreased by 15%. Given that Tom's allowance would increase by another 40% if he had received $830 more from his Mothers, find the difference in the children's monthly allowances.
| |
Tom |
Fanny |
| Before |
1 u |
1 u |
| Change 1 |
+ 0.25 u |
- 0.15 u |
| After 1 |
1.25 u |
0.85 u |
| Change 2 |
+ 0.5 u |
No change |
| After 2 |
1.75 u |
0.85 u |
Increase in Tom's allowance
= 25% x 1 u
=
25100 x 1 u
= 0.25 u
Decrease in Fanny's allowance
= 15% x 1 u
=
15100 x 1 u
= 0.15 u
Increase in Tom's allowance if his Mothers gave another $830
= 40% x 1.25 u
=
40100 x 1.25 u
= 0.5 u
0.5 u = 830
1 u = 830 ÷ 0.5 = 1660
Difference in the allowance between Tom and Fanny
= 1.25 u - 0.85 u
= 0.4 u
= 0.4 x 1660
= $664
Answer(s): $664
