Problem Solving

Can someone show me how to solve this one please...

three grades of milk are 1 percent, 2 percent, and 3 percent fat by volume. If x gallons of 1 percent, y gallons of 2 percent, and z gallons of the 3 percent grade are mixed to give x+y+z gallons of a 1.5 percent grade, what is x in terms of y+z?

a) y+3z
b) (y+z)/4
c) 2y+3z
d) 3y+z
e) 3y+4.5z

(the answer is A)... thanks!

(1/100)*x+(1/100)*y+(1/100)*z = 1.5/100(x+y+z)
solve we get
x = y+3z

Thank you!


NOTE FOR ANYONE ELSE WHO LOOKS TO THIS:

1/100)*x+(1/100)*y+(1/100)*z = 1.5/100(x+y+z)
solve we get
x = y+3z


this is the correct methodology, however, notice that a "2" and "3" should be subsituted in the numerator for the fractions for variables y and Z.. thus equation will look as follows, in contrast to that above:

1/100)*x+(2/100)*y+(3/100)*z = 1.5/100(x+y+z)
solve we get
x = y+3z


again, thank you for the help!