Balloons: How many balloons were in the box?

[Love21]

A company sells boxes of balloons in which the balloons are red, green or blue. Mary purchased a box of balloons in which
1/3 were red. If there were half as many green balloons as red ones and 18 blue balloons. How many balloons were in the box?

So i know that green = 1/2 red
red = 1/3 of total
blue = 18

i'm getting stuck on how to finish out this problem
help would be appreciated!!

 

[stapel]

A company sells boxes of balloons in which the balloons are red, green or blue. Mary purchased a box of balloons in which 1/3 were red. If there were half as many green balloons as red ones and 18 blue balloons. How many balloons were in the box?

i'm getting stuck on how to finish out this problem

Try using what you learned back in your previous algebra courses:

i) Pick a variable for the total number of balloons.

ii) Write an expression, in terms of the variable in (i), for the number of red balloons.

iii) Write an expression, in terms of the expression in (ii), for the number of green balloons.

iv) Note the value provided for the number of blue balloons.

v) Sum (ii), (iii), and (iv), and set equal to (i).

vi) Solve the linear equation in (v).

vii) Use the definitions in (i) through (iv) to interpret the value in (vi) in terms of the original question.

Have fun!

Eliz.