Answer:
8/9 hours
Explanation:
We need to determine how much of the lawn Mel has to mow
1 lawn - 1/3 of the lawn = 3/3 - 1/3 = 2/3
We can use a ratio to solve
3/4 lawn 2/3 lawn
-------------- = ------------
1 hour x hours
Using cross products
3/4 x = 1 * 2/3
3/4x = 2/3
Multiply each side by 4/3
4/3 * 3/4x = 2/3 * 4/3
x = 8/9
8/9 hours