If the cost of 100 copies is $3.10, how many copies can be made for $155?

Question

If the cost of 100 copies is $3.10, how many copies can be made for $155?

Answer 1

Think of it as a proportion problem:

¹⁰⁰/_3.1 = ^x/₁₅₅ (If we make 100 copies for $3.10, how many can be made for $155?)

 

Multiply both sides by 155:

^{100 * 155}/_3.1 = x

^{100 * 50}/₁ = x

5000 = x