In one day, the Tool Shed rented out 25 self-propelled and riding
mowers for a total fee of $900. The
daily rental for the self-propelled
mowers was $20 and for the riding
mowers was $40. Find the number
of self-propelled and the number of
riding mowers rented for that day.
x + y = 25
20x+ 40y = 900
Substitute the value for x into the first equation and solve for y.