Answer:
21
Step-by-step explanation:
The bus fare in a city is $1.50. People who use the bus have the option of purchasing a monthly coupon book for $21.00. With the coupon book, the fare is reduced to $0.50. Determine the number of times in a month the bus must be used so that the total monthly cost without the coupon book is the same as the total monthly cost with the coupon book.
Solution
Let
y = number of bus fares.
Cost of bus fares without coupon book = 1.50y
Cost of bus fares with coupon book = .50y + 21
Equate cost of bus fares without coupon book and cost of bus fares with coupon book
1.50y = .50y + 21
Subtract .50y from both sides of the equation
1.50y - .50y = .50y + 21 - .50y
1.00y = 21
Divide both sides by 1.00
y = 21 / 1.00
y = 21 times
