Hole Digging word problem

Question

if it takes two people 20 minutes to dig a hole and it takes one of the people 25 minutes to dig the hole by himself, how long will it take the second person to dig the hole individually

Answer 1

1/20 = 1/25 + 1/t, where t = the amount of time it takes the 2nd person to dig the hole working alone

 

5t = 4t + 100

t = 100

 

It will take the 2nd person 100 minutes, or 1 hour and 40 minutes, to dig the hole alone