Answer:
3 x 10 = 30 man-days per house
1. divide each number by 6 and you get 4:3 answer c
2. 1x+4x=45 (the ratios give you how many of each you have)
5x=45 so x=9 that is the smallest number
3. percent means out of 100 so 490/100 4.9
4 percent means out of 100 so .5/100 5/1000 = .005
