23) 17/30
41) 3/10 because 3/10 + 7/10 = 10/10 or 1.
We should request a completion time of
223 work-days.
To find the contribution of each man (this is a sexist problem as women could work as well, but that’s besides the point) take 5/2 and then multiply that value by 20 and you’ll find it takes 50 hours for two men to do it.
Answer: 50 hours
Subtract 13 from both sides:


Divide both sides by -5. Since this is a negative number, you have to invert the inequality sign:

Which means
What are the choices, it’s blank.