Answer: 10/9 hours
Work Shown:
3/20 of a yard = 1/6 of an hour
(20/3)*(3/20 of a yard) = (20/3)*(1/6 of an hour)
1 yard = 20/18 of an hour
1 yard = 10/9 of an hour
In the second step, I multiplied both sides by 20/3 to have that initial "3/20 yard" turn into "1 yard".
The improper fraction 10/9 is equivalent to the mixed number 1 & 1/9. Both are roughly equivalent to the decimal value of 1.11; so it takes roughly 1.11 hours for Jerry to mow the full lawn.