Question

Kyoko is reading a book by her favorite author. She read the first 20 pages in One-half of an hour. Reading at the same pace, Kyoko wants to determine if she’ll have enough time to finish the book before she has to go to bed.

Reading Time
On a coordinate plane, a graph titled Reading Time has number of hours on the x-axis, and number of pages on the y-axis. A straight line goes through (0, 0), (0.5, 20), and (2, 80).


According to the graph, which statement must be true?
It will take her 2 hours to read 60 pages.
It will take her 3 hours to read 120 pages.
It will take her 4 hours to read 180 pages.
It will take her 5 hours to read 210 pages.

Answer 1

The line has slope 20 pages / 0.5 hour = 40 pages per hour, so pages = 40 × hours. For 120 pages: hours = 120/40 = 3. Thus "It will take her 3 hours to read 120 pages" is true; the others are false.