150 times (X-5)= 120x.
150x-750= 120x
150 x-750+750 = 120 x+750
150x= 120x+750
150 x- 120 x = 120 x+750- 120 x
30x=750
30x divided by 30=750 divided by 30
x=25
120 times 25=3000 (sets) A: There are 3000 sets of clothes in this batch.