Question

Please help

Kirsten can spend up to $50 on rock to landscape her yard. She decides to use both pebble rock and river rock. Pebble rock costs $2 per pound, and river rock costs $5 per pound. Which graph best models this situation?



A

B

C

Answer 1

The graph that best models this situation is option A

How to solve word problem

We represent y as the amount of pebble rock and x as the amount of river rock,

Cost of y pebble rock at $2 per pebble = 2y

Cost of x river rock at $5 per river rock = 5x

Total cost is

T = 2y + 5x

And the constraint on the total cost not exceeding $50 would be:

2y + 5x <= 50

The non-negativity constraints for the amounts of rock remain the same:

x >=0, y >=0

Graphing the inequality 2y + 5x <=50 on a coordinate plane with x and y axes.

The area below (including on the line) would represent the valid combinations of x (river rock) and y (pebble rock) that satisfy Kirsten's budget constraint. Option A is the correct answer.