Verified answer

Answer:

10 days

Step-by-step explanation:

Solution 1:

Solving for the rate ,

Given: W = 1 , N = 20 Men , T = 4 days

W = NRT

W = 20(R)(4)

1/80 = R

Solving for the time ,

Given: W = 1 , N = 8 men , T = ? , R = 1/80

W = NRT

1 = 8(1/80)T

1 = 8/80T

1 = 1/10T

1×10 = T

10 = T

Solution 2:

20 : 8 = N : 4

20 × 4 = 8×N

80 = 8N

80/8 = N

10 = N