Answer:
B = Blue
Y = Yellow
G = Green
P = Pink
The info that we have is:
3*B = Y
(1/2)Y = G
P = (3 + 1/4) gal
P = G + 3/4 gal.
So we have 4 equations. The first step is replacing the third equation into the fourth equation, and get:
G + 3/4 gal = (3 + 1/4) gal
G = (3 + 1/4) gal - 3/4 gal = (2 + 2/4) gal
Now we can replace this into the second equation ((1/2)*Y = G) to find the value of Y.
(1/2)Y = (2 + 2/4) gal
Y = 2*(2 + 2/4) gal = (4 + 1)gal = 5 gal.
Now we can replace this into the first equation and get:
3*B = 5gal
B = 5/3 gal = (1 + 2/3)gal
So the total amount of paint used is:
T = P + G + Y + B = (3 + 1/4) gal + (2 + 2/4) gal + 5gal + (1 + 2/3)gal
T = (11 + 3/4 + 2/3)gal
T = (11 + 9/12 + 8/12)gal = (11 + 17/12)gal = (11 + 1 + 5/12)gal = (12 + 5/12) gal.