To represent the amount of money Johnnie will earn based on the number of yards he mows, you can use the following inequality:
Let \( y \) be the number of yards Johnnie mows.
Since Johnnie earns $7 for every yard mowed, his earnings can be expressed as:
\[ 7y \]
Given that he mows at least 16 yards, we can set up the inequality:
\[ y \geq 16 \]
Now, substituting the minimum value into the earnings expression, we find the minimum amount Johnnie will have in his account:
\[ \text{Earnings} = 7y \] \[ 7y \geq 7 \times 16 \] \[ 7y \geq 112 \]
So the inequality for Johnnie's earnings based on mowing at least 16 yards is:
\[ 7y \geq 112 \]
This means that Johnnie will have at least $112 in his account if he mows at least 16 yards.