Question 150510
gian and arwin can finish a project in 4 2/3 hours. gian can do it alone in half as much time as arwin can do the job. How long will it take Arwin to do the job alone.
.
Let G = time it takes gian to do the the job alone
and A = time it takes arwin to do the the job alone
.
Since you have two unknowns, you'll need to find two equations.
.
G+A = 4 2/3 (or 4.667 hours) (equation 1)
G = (1/2)A  (equation 2)
.
Use the definition of G (from equation 2) and substitute it into equation 1 to find G:
G+A = 4.667
(1/2)A+A = 4.667
Multiply both sides by 2 to rid ourselves of all denominators:
A + 2A = 9.334
3A = 9.334
A = 3.11 hours (time it take arwin to do the job alone)
Or, 3 hours 7 mins
.
G = (1/2)A = 1.56 hours (time it takes gian to do the job alone)
Or 1 hour 34 mins