Question

Tom and sam can finish a plowing job in two hours if they work together. tom working alone can do the job in 7 hours. how long would it take sam to finish the same job alone

Answer 1

Tom’s Rate + Sam’s rate = Together rate

Therefore, Sam’s rate = Together rate – Tom’s rate

 

Sam's rate = 1/x job per hour

Together rate = 1/2 job per hour
Tom's rate = 1/7 job per hour

Therefore,
1/x = 1/2 – 1/7

 

(multiply the equation by 14x; 14x is the lowest common multiple of the denominators)

 

14 = 7x – 2x

5x = 14
x = 2.8 hours

 

2.8 hours = 2 hours + (0.8 X 60) minutes

0.8 X 60 = 48 minute

Therefore, 2.8 hours = 2hrs 48 mins

 

How long it would take Sam to finish the same job alone is 2hrs 48 mins.