Ward works at a clothing store, and works on commission.

the amount he makes each week depends on how much clothing he sells, and he also receives a weekly amount regardless of his sales.
edward also has to pay for his meals during his shifts, which detracts from his income.

edward’s income can be modelled by the following equation:

i = 100+12j+5t+7s+5h−8m

where i is his income,
j is the number of jeans he sells,
t is the number of t-shirts he sells,
s is the number of shorts he sells,
h is the number of hats he sells, and
m is the number of meals he buys.

if edward makes
$237 in a week and sells:
3 pairs of jeans,
10 t-shirts, and 4 hats,
and buys 4 of his meals.

how many pairs of shorts did he sell?