Answer:
Aryiah spends 21 dollars
Explanation:
Aryiah and Mike spend some money. Aryiah spends 4 dollars more than what Mike spends. Both together spend 38 dollars.
Let us denote the amount spent by Aryiah with
and the amount spent by Mike with
. Here
and
are in dollars.
Aryiah spent 4 more dollars than Mike ⇒

Both together spend 38 dollars ⇒

Substituting first equation in the second,

∴ Aryiah spends 21 dollars and Mike spends 17 dollars.