Question

Duane and Mick are saving their money to build a tree house. Duane adds $5 to their piggy bank every week. Mick adds $2 every week. So far they have $45. How many weeks have they been saving money?

Answer 1

Set up the equation, 

5x+2x=45

x means weeks, x=weeks,

so 5x+2x=7x

which makes it, 

7x=45

Then just divide,

$\frac{7x}{7} = \frac{45}{7}$

x=6.4 (rounded)

So, they have been saving for about, six and-a-half weeks.