Answer:

36 days

Step-by-step explanation:

Inverse variation equation:  

y = k/x

Men: y

Number of days: x

Constan of variation: k

Find the constant:

8 = k/90

k = (8)(90)

k = 720

Find the number of days to finish the job when 20 men work:

20 = 720/x

x = 720/20

x = 36 days

Answer:

225

Step-by-step explanation:

8 = 90

4= 45

8+8+4=20

90+90+45=225

answer: 225

nakuha kopo yung 4 at 45 dahil hinati ko po sa half yung 8 at 90