A business rents bicycles and skates. Bicycle rentals cost $25 per day and skate rentals cost $20 per day. The business has 20 rentals today and makes $455. How man bicycle rentals did the the business have today?
Call the number of bike rentals = x
And the number of skate rentals = 20 - x
So
25x + 20 ( 20 - x) = 455 simplify
25x + 400 - 20x = 455
5x + 400 = 455 subtract 400 from both sides
5x = 55 divide both sides by 5
x =11 = number of bike rentals
