Answer:
part A; B and Part B; pencils
Step-by-step explanation:
you want to find out how many pens and pencils you cn buy with that 90$ so you want to do
.75y+.15x=90
pens=50
pencils=50
but you want to add .75+.15 which = .90
then you divide 90/.90
and that equals 100
then split it up and each gets 50