Question

The tread depth of the tires on your family's new car is 3/8 inch. you predict that, as a result of driving the car, the change in tire tread depth will be about -3/64 inch per year.

A. write a variable expression for the tire tread depth after y years of driving. Use your expression to make a table showing the tire tread depth after 1,2 an 3 years.


b. Tires should be replaced when the tread depth is 1/16 inch. extend your table from part (a) to find the approximate number of years the car can be driven before the tires need to be replaced.

Answer 1

Y = 3/8- ((-3/64)x) this is the variable expression.
just make y= 1/16 to find the number of years.
plug 1,2,3 into x to find the amount of tread left after each year.

Answer 2

Nancy, you have a double negative, your equation would have the tread depth increase.
it should have been

depth = 3/8 - (3/64)t where t is number of years.