Chandler Heisinger buys a monthly metro card, which entitles him to unlimited subway travel in New York City, for $81 per month.
Without the MetroCard, each subway ride costs $2. How many rides per month would Chandler have to take so that the cost of he rides with the MetroCard is less than the cost of the rides without the MetroCard?
Let be the number of rides Chandler takes in a month. Then the cost with the MetroCard is still $81, but the cost without the MetroCard is . So we can set up an equation representing what we want: "The cost with a MetroCard of r rides in a month is less than the cost without a MetroCard." In equations, Thus, at a minimum, Chandler must take 41 rides for his MetroCard to be cheaper than not having it.
Explanation: If he washes 75 cars in 5 days; and you need to find how many days it takes to wash 90 you do 75 divided by 5 which is 15; so he washes 15 cars in a day, then do 90 divided by 15 which is 6 days