Answer :

iGreen
S = N + 4
N = H - 8
S = 15

S = N + 4

Plug in 15 for 'S':

15 = N + 4

11 = N

N = H - 8

11 = H - 8

Add 8 to both sides:

19 = H

So Hector receives $19 for allowance.
[tex]\text{Sam}=\text{Nathan+4}\\ \text{Nathan}=\text{Hector}-8\\ \text{Sam}=15\\\\ 15=\text{Nathan+4}\\ \text{Nathan}=11\\\\ 11=\text{Hector}-8\\ \text{Hector}=19[/tex]