I need help with word problem

Question

Vivian bought 7 rainbow and balloon stickers for her little sister . The rainbow sticker cost 3 cents apiece and the balloon sticker cost 1 cents apiece. If Vivian spends exactly $.13, how many of each type of sticker did she buy?

Answer 1

You can solve this problem by creating two equations with two unknowns and using elimination to find the number of each type of stickers.

Let's use the variable ,r, to represent the NUMBER of rainbow stickers purchased and the variable ,b, to represent the NUMBER of balloon stickers purchased.

Since she bought a total of 7 stickers, we can write the following equation:

r + b = 7

Also, we can use the price of each kind to write the following equation (using cents):

3r + 1b = 13

Now we can combine these equations and use elimination to find the number of balloon stickers, b:

r + b = 7

3r + 1b = 13

Multiply the first equation by -3:

r + b = 7 becomes -3r - 3b = -21

Now combine these two equations:

-3r - 3b = -21

3r + 1b = 13

-2b = -8

b= 4

She bought 4 balloon stickers.

This would mean that she bought 3 rainbow stickers.