Xavier's and Shannon's monthly allowances were the same at first. Xavier's allowance increased by 30% while Shannon's decreased by 15%. Given that Xavier's allowance would decrease by another 30% if he had received $1170 less from his mothers, find the difference in the children's monthly allowances.

	Xavier	Shannon
Before	1 u	1 u
Change 1	+ 0.3 u	- 0.15 u
After 1	1.3 u	0.85 u
Change 2	- 0.39 u	No change
After 2	0.91 u	0.85 u

Increase in Xavier's allowance
= 30% x 1 u
= ³⁰₁₀₀ x 1 u
= 0.3 u

Decrease in Shannon's allowance
= 15% x 1 u
= ¹⁵₁₀₀ x 1 u
= 0.15 u

Decrease in Xavier's allowance if he had received $1170 less from his mothers
= 30% x 1.3 u
= ³⁰₁₀₀ x 1.3 u
= 0.39 u

0.39 u = 1170

1 u = 1170 ÷ 0.39 = 3000

Difference in the allowance between Xavier and Shannon
= 1.3 u - 0.85 u
= 0.45 u
= 0.45 x 3000
= $1350

Answer(s): $1350