If Sam can do a job in 4 days that Lisa can do in 6 days and Tom can do in 2 days, how long would the job take if Sam, Lisa, and Tom worked together to complete it?
A. 0.8 days
B. 1.09 days
C. 1.23 days
D. 1.65 days
E. 1.97 days
thanks.
Do this the same way I did the other one.
To find out how long it would take Sam, Lisa, and Tom to complete the job together, we need to calculate their combined work rate.
First, let's find out how much work each person can do in one day.
- Sam can do the job in 4 days, so his work rate is 1 job / 4 days = 1/4 job per day.
- Lisa can do the job in 6 days, so her work rate is 1 job / 6 days = 1/6 job per day.
- Tom can do the job in 2 days, so his work rate is 1 job / 2 days = 1/2 job per day.
Now, let's add up their individual work rates to find the combined work rate when they work together:
Combined work rate = Sam's work rate + Lisa's work rate + Tom's work rate
Combined work rate = 1/4 + 1/6 + 1/2 = 3/12 + 2/12 + 6/12 = 11/12 job per day
So, when Sam, Lisa, and Tom work together, they can complete 11/12 of the job in one day.
To find out how long it would take to complete the entire job, we can divide 1 job by the combined work rate:
Time = 1 job / Combined work rate = 1 / (11/12) = 12/11 = 1.09 days
Therefore, the correct answer is B. 1.09 days.