<p>Anna Maria bought 3 more boxes of pencils than boxes
of erasers. There are 10 pencils in each box of pencils
and 20 erasers in each box of erasers. If the number of
pencils Ihal Anna Maria bought equals the number of
erasers that she bought, how many pencils did Anna
Maria buy?</p>
<p>Why is the answer 60? I’m having trouble setting up equations/variables on this one</p>
<p>So here’s how I did it.
I let x= the number of boxes of erasers Anna bought. Since Anna bought three more boxes of pencils than erasers, the number of boxes of pencils she bought is x+3
So, the number of pencils would be (10)(x+3), which is the number of pencils in each box times the number of boxes of pencils she bought. The number of erasers would be 20x which is the number of erasers in each box times the number of boxes of erasers she bought. So since #pencils = #erasers, (10)(x+3)=20x. Solve for x and x=3, which is the number of boxes of erasers she bought. So she bought 6 boxes of pencils. 10 pencils in each box means 60 pencils.</p>
<p>Thank you so much! What a clear explanation! :)</p>
<p>No problem ;)</p>