Answer: Ethan spent 4 hours in mowing lawn.
Step-by-step explanation:
Given per hour mowing rate = $6.
Per hour bagging groceries = $7.50
Let us assume number of hours Ethan spent on mowing lawns = x hours.
Number of hours spent in bagging groceries = y.
The difference between the hours of bagging groceries and mowing lawns is 10.
Therefore,
y-x = 10 ----------(1)
Total amount he made = $129.
Therefore,
6x + 7.50y = 129 -------------------(2).
Solving first equation for y and substituting in second equation.
y -x=10.
y = x+10.
6x +7.50(x+10) = 129
6x +7.50x + 75 = 129.
13.50x +75 = 129.
Subtracting 75 from both sides, we get
13.50x +75 -75= 129-75
13.50x = 54
Dividing both sides by 13.50, we get
13.50x/13.50 = 54/13.50
x = 4.
Plugging x=4 in first equation y = x+10, we get
y = 4+10= 14.
Therefore, Ethan spent 4 hours in mowing lawn.
