Answer:
5/9
Step-by-step explanation:
Context for variables
sw: number of sweaters
j: number of jeans
sk: number of skirts
The following three equations are established from the question:
sw + j + sk = 120
sw/j = 8/3
j/sk = 3/4 or sk/j = 4/3
Dividing the first equation by j, we get:
sw/j + j/j + sk/j = 120/j
8/3 + 1 + 4/3 = 120/j
5 = 120/j
j = 120/5 = 24
sw = 24*8/3 = 64
sk = 24*4/3 = 32
After the replacement the new number of jeans and skirts are:
j' = 24 - 4 = 20
sk' = 32 + 4 = 36
the new ratio of jeans to skirts is:
j'/sk' = 20/36 = 5/9