Act Math Practice

Coordinate Geometry Answer 5

Coordinate Geometry Answer 5:

5. Marta has just bought a new pair of tennis shoes. She wants to wear the new running shoes to run up and down a hill near her house. The measurements of the hill can be placed on a two dimensional linear graph on which x = 5 and y = 165. If the line crosses the y axis at 15, what is the slope of this hill?

A. 10

B. 20

C. 30

D. 36

E. 75

The correct answer is C.

In order to calculate the slope of a line, you need this formula:

y = mx + b

Note that m is the slope and b is the y intercept.

Now substitute the values:

y = mx + b
165 = m5 + 15
165 - 15 = m5 + 15 - 15
150 = m5
150 ÷ 5 = m5 ÷ 5
30 = m

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