Answer=24 blue marbles and 3 red marbles
r=red marbles
b=blue marbles
b=3(r+5)
27=b+r
substitue b for '3(r+5)'
27=3(r+5)+r
27=3r+15+r
27=4r+15
subtract 15 from both sides
12=4r
divide both sides by 4
3=r
There are 3 red marbles
27=b+r
27=b+3
subtract 3 from both sides
24=b
There are 24 blue marbles