6 shirts and 8 sweater cost $152
or
5 shirts and 7 sweaters cost $132
$152 - $132 = $ 20 that was taken away from both things being gone (1 sweater and one shirt)
The answer could be that a shirt costs $10 and a sweater cost $10 or it could mean the shirt cost $9 and the sweater costs $11 or it could swap and be the shirt costs $11 and the sweater costs $9. Or the shirt costs $1 and the sweater costs $19 or A shirt costs $3.50 and the Sweater costs $16.50.