Kim roof was leaking and the hardware store said a new roof sealant product would fix the roof. Each can of roof sealant covers 100 square feet. the roof was 23 feet long and 15 feet wide. How many cans of roof sealant is needed to buy?

First we need to find the area of roof we need to cover:

Length * Width = Area

23 * 15 = 345

Now we know that we must cover 345 square feet of roof.

Then, we must divide the area of roof by the area each can will cover:

345 / 100 = 3.45

Since it would likely be impossible to buy 45% of a can, we must round up since at the same time we can't leave part of the roof uncovered.

3.45 rounded up is 4.

So, you need 4 cans of sealant.