Duane and mick are saving their money to build a treehouse. duane adds $5 to their piggy bank every other week. mick adds $2 every week. so far they have saved $45. how many weeks have they been saving their money?

They have been saving their money for 10 weeks.

Duane = $5 every two weeks

Mick = $2 every week.

Get the value of Duane's weekly contribution = $5 / 2 = $2.5

Duane's share + Mick's share = $45

$2.5x + $2.0x = $45 = = = >> equation can also be x (2.5 + 2) = 45

$4.5x = $45

$4.5x / $4.5 = $45 / $4.5

x = 10 weeks.

To check:

$2.5 (10) + $2 (10) = $45

$25 + $20 = $45

$45 = $45