Question

Solve and round your answer to the nearest hundredth. Working alone, Bill can tar a roof in 13 hours. Harry can tar the same roof in 11 hours. How long would it take them if they worked together?

A) 7.87 hours

B) 8.25 hours

C) 6.35 hours

D) 14.4 hours

Answer 1

Solving this expression gives approximately 7.87 hours, so the correct answer is: A) 7.87 hours. This means that if Bill and Harry work together, they can tar the roof in approximately 7.87 hours.

Step-by-step explanation:

To determine how long it would take Bill and Harry to tar the roof together, we can use the formula:

Work rate = 1/Time.

Let B be Bill's work rate and H be Harry's work rate. Then:

B = 1/13 roofs per hour

H = 1/11 roofs per hour

When they work together, their combined work rate is the sum of their individual work rates:

B+H=1/13+1/11 roof per hours

To find the time it takes for them to complete the task together, take the reciprocal of their combined work rate:

Time=1/B+H

Now, substitute the values and calculate:

Time = 1/(1/13)+(1/11)

Solving this expression gives approximately 7.87 hours, so the correct answer is: A) 7.87 hours. This means that if Bill and Harry work together, they can tar the roof in approximately 7.87 hours.