Question

Bob purchased a bus pass card with 320 points. Each week costs 20 points for unlimited bus rides. The graph shows the points remaining on the card over time in weeks. Determine the value of f(10), and explain what it represents.

Answer 1

f(10) = 320 - (20 * x)

Explanation:

Plug in for x

f(10) = 320 - (20 * 10)

Multiply

f(10) = 320 - 200

Subtract

f(10) = 120

Bob has 120 points left after 10 weeks of riding the bus.

Answer 2

The value of f(10) is 120 points.

Explanation:

Given,

Total points = 320,

The points spent in a week = 20,

So, the points spent in x weeks = 20x,

Thus, the remaining points ( say f(x) ) = Total points - points spent in m weeks

f(x) = 320 - 20x

If x = 10,

The remaining points after 10 weeks,

f(10) = 320 - 20(10) = 320 - 200 = 120 points