How to solve the following?

Question

Ten people can paint 60 houses in 120 days, so five people can paint 30 houses in how many days?

Answer 1

You've reduced the work force by half, but you ALSO reduced the work load by half, so the rate stays the same.  120 days.

Answer 2

120 days

Answer 3

10 people : 60 houses : 120 days

= 1 person : 6 houses : 12 days

5(1 person : 6 houses : 12 days)

= 5 people : 30 houses : 60 days

∴ 5 people can paint 30 houses in 60 days.

Answer 4

Ten people can paint 60 houses in 120 days

so 10 people can do 1 house every 2 days.

so 1 person can do 1 house every 20 days

1 person and 30 houses would be 20*30 = 600 days

with 5 people that becomes 600/5 or 120 days.

,

Answer 5

Ten people can paint 60 houses in 120 days

Ten people can paint 30 houses in 60 days

Five people can paint 30 houses in 120 days

Answer 6

Using ratio and proportion:

10:60: 120 = 5: 30: x

10/60 (120)  =  5/30 (x)

1200/60 = 5x/30

60(5x) = 1200 (30)

300x = 36000

x =  120 days

Answer 7

Set this up as an equation.  You have how many man-days per house:

10people * 120days/60 houses = 20 man-days per house

so... 5 people * x days/30 houses =20 man-days per house

Solve for x to get 120 days