2023 AMC 8

Complete problem set with solutions and individual problem pages

Problem 9 Easy

Malaika is skiing on a mountain. The graph below shows her elevation, in meters, above the base of the mountain as she skis along a trail. In total, how many seconds does she spend at an elevation between 4 and 7 meters?

  • A.

    6

  • B.

    8

  • C.

    10

  • D.

    12

  • E.

    14

Answer:B

Solution 1

We mark the time intervals in which Malaika's elevation is between 4 and 7 meters in red, as shown below:

The requested time intervals are:

- from the 2nd to the 4th seconds - from the 6th to the 10th seconds - from the 12th to the 14th seconds In total, Malaika spends (4-2) + (10-6) + (14-12) = \boxed{\textbf{(B)}\ 8} seconds at such elevation.

 

Solution 2

Notice that the entire section between the 2 second mark and the 14 second mark is between the 4 and 7 feet elevation level except the 2 seconds where she skis just under the 4 feet mark and when she skis just above the 7 feet mark, making the answer 14-2-2-2=\boxed{\textbf{(B)}\ 8}.