Question 507179
Pete=x
Phillip=y
Brian=z

x=1/3z
y=z+5

x+y+z=40
now change all to z

(1/3z)+(z+5)+z=40
 
multiply each by 3 to cancel out the 1/3z
now you have

3z+15+3z=105
now subtract 15 you have

3z+3z=90
now divide all by 3

z+z=30
2z=30
z=15

x=1/3z
x=1/3(15)
x=5

y=z+5
y=15+5
y=20

x+y+z=40
5+20+15=40