Savannah buys a $40 gift card to her favorite smoothie shop. each smoothie costs $4. she wants to have at least $10 left on her
card at the end of this month. the inequality below relates x, the number of smoothies she could buy between now and the end of
this month with her gift card balance.

I think the most simple way to solve this is by writing out a few general expressions;

$40 - $10 = $30

$30 - 4x = y

$10 + y = z

X = Amount of Smoothies

Y = Total Amount left

Z = Total + the $10

to find the total number of combinations, multiply the quantity of each item by each other:

2 pairs of shoes x 3 pairs of shorts = 6 different combinations.