Cyber High Math Question?

Question

If a person can complete a job in 8 hours and their friend complete the same job in 6 hours, what portion of the job would be completed if the two of them worked together for two hours?

Answer 1

Person 1 can complete the job in 8 hours, so they complete 1/8th of the job each hour.  

Person 2 can complete the job in 6 hours, so they complete 1/6th of the job each hour.

 

They each work for 2 hours

(1/8 )x 2 = 2/8 or 1/4

(1/6) x 2 = 2/6 or 1/3

 

to get the total, add 1/4 and 1/3.  the least common denominator is 12

 

(1/4) x 3 = 3/12     (1/3) x 4 = 4/12

 

3/12 + 4/12 = 7/12 or 0.583 x 100 = 58.3%