Question

12) Twenty cubic feet of marble can weigh 3400 pounds, plus or minus 100

Answer 1

Answer:

Let's suppose that one cubic foot of marble is x.

20x = 3400

But because the weight has a range of +-100, then 20x is between 3300 and 3500. Write it like this:

3300<20x<3500

Divide by 20:

165<x<175

The meaning of this is that one cubic foot of marble weight between 165 and 175 pounds