Answer:
3 & 2/3 pounds
Explanation:
You have $10.25 and want to buy Sweet Tarts at $2.80/pound.
Before I show you the "math" way to do it, and because they asked "about how many pounds" did she buy, let's just think about it for a minute:
Could we buy one pound? Sure, that's just 2.80.
Could we buy two pounds? Yeah, that's 5.60.
Three pounds? Yep, that's only 8.40, and I have 10.25.
Four pounds? Ruh roh, we don't have another 2.80 left, do we?
No, we don't. We have 10.25 - 8.40 = $1.85 left.
We can't buy a pound with that, but could we buy half a pound? Well, half of 2.80 is 1.40, so yes, we could buy 0.5 pounds more.
Maybe they'd let us buy by the quarter-pound, can we afford a quarter-pound? In our heads we can figure, "Half of 2.80 is 1.40, and half of that is a quarter, and that's 0.70. But we only have 45 cents left, so no."
I hope all that made sense. A lot of times it's better to get away from "this is a math problem I need to solve," and just think about how it is in the real world.
Okay, so do you want the "math" way now?
$10.25 ÷ $2.80 per lb
When you divide, the units of "dollars" cancel out and the "pounds" move to the top.
10.25/2.8 = 3.66 lb
Does that ".66" look familiar? It should, because it's two-thirds. So you can buy "about" 3 2/3 pounds of yummy SweeTarts®.