Answer:
His brother will take 3.5 hours or hours to mow 21 lawns
Step-by-step explanation:
Given:
His brother mows 6 lawns in an hour.
To find the time his brother takes to mow 21 lawns.
Solution:
We will unitary method to find the time he will take to mow 21 lawns.
If 6 lawns are mowed in 1 hour
So, 1 lawn will me mowed in = hours.
Thus 21 lawns will be mowed in = hours.
Thus, his brother will take 3.5 hours or hours to mow 21 lawns