Question

If 4 persons can paint a house in 9 days, then 5 persons can paint the same house in * a:12 days
b:2(2/9) days
c:10 days
d:7(1/5) days

Answer 1

Answer:

Two people working together = 14 hours

Let the people can paint a house be x.

Working individually, one people takes 2 hours more than it takes the other person to paint =

x

1

+

x+2

1

So,

x

1

+

x+2

1

=

14

1

x

2

+2x

2x+2

=

14

1

28x+28=x

2

+2x

x

2

−26x−28

Using quadratic formula,

2a

−b±

b

2

−4ac

to find the roots of the quadratic equation

⇒

2×1

26±

(−26)

2

−4×1×(−28)

⇒

2

26±

788

⇒

2

26±28.07

x=27.03, x=−1.03

x cannot be negative.

Each person working individually to paint the house = 27 + 2 = 29 hours.