Jack and Serena can write a lab report together in $6$ hours. If all people work at the same rate, how many hours would it take to write a lab report if Kay joins Jack and Serena?

  4 hours

Step-by-step explanation:

If all work at the same rate, the time required is inversely proportional to the number of people on task. If the number of writers goes from 2 to 3 (is multiplied by 3/2), the time required will be 2/3 of that for 2 people:

  (2/3)(6 hours) = 4 hours

If Kay joins Jack and Serena, the lab report can be done in 4 hours.

set each factor equal to 0

4x-3 = 0

2x-1 = 0

solve for x.

4x-3=0

4x=3

x= 3/4

solve for x. 

2x-1= 0

2x= 1

x= 1/2

your answer should be 1/2 is less than or equal to x and 3/4 is greater than or equal to x

it has changed from the width and the height.

step-by-step explanation: