Question

Emilio owns a bakery. The number of boxes of cookies he has left on a Monday is represented by the function x + y = 42, where y is the number of boxes of cookies remaining in the bakery and x is the number of hours since he opened the bakery. How many boxes did he have at the start of business

Answer 1

The number of hours since the bakery opened, plus the number of remaining boxes is equal to 42. 

x + y = 42 

So the number of boxes remaining is equal to y, and 

y = 42 - x, the number of hours the bakery was open. 

So at the start of the day, the bakery was open for 0 hours, and y, the number of boxes "remaining" at the start of the day, will be equal to 42 - 0 = 42.