Manuela found a great deal on pens at 3 for .99, it was such a god deal that she decided to buy two-dozen pens. how much did she pay for the pens?

explain

A dozen = 12.
Two dozen = 24

Set up a proportion:



Then we need to solve for X (the amount of money she paid)

Cross multiply to get 3x = 24(.99)
3x = 23.76
x= $7.92

Or you can do it another way if you knew 3 goes into 24 8 times, so you can multiply .99x8 = $7.92