How do you solve this story problem?

Question

karen can wash the walls in a certain room in 3 hours and erika can wash these same walls in 2 hours. How long would it take them to complete this task if they work together? Would it have gone any faster if they would have used fantastic? 

Answer 1

Not clear what the second question is asking. But, for the first question, you set up the formula as

 

(1/2) + (1/3) = 1/x.         Least Common Denominator = 6x. So multiply both side by 6x.

3x + 2x = 6                     Combine like terms.

5x = 6                             Divide by 5 on both sides.

 

X= 1.2

 

So if Karen and Erica work together, it would take them 1.2 hours.