Lisa reads an equal number of pages of a book every week. The graph below shows the number of pages of the book left to read, y,
after x weeks: A graph titled Lisas Book Reading shows Number of Weeks on the x-axis and Number of Pages Left on the y-axis. The scale on the x-axis shows numbers from 0 to 6 at increments of 1, and the scale on the y-axis shows numbers from 0 to 350 at increments of 50. A straight line joins the ordered pairs 0, 250 and 1, 200 and 2, 150 and 3, 100 and 4, 50 and 5, 0.
Which equation best models the relationship between x and y?
y = −50x + 250
y = −5x + 50
y = −50x + 350
y = −5x + 250
In case you don't realize that the graph starts at 250 and decreases by 50 for each increase of 1 in x, you can see if any of the equations match the given points. The only one that does is the first one:
Solution Let E1 be the event that coin 1 is selected and E2 the event that coin 2 is selected. Let F be the event that exactly 7 of the 10 flips lands on heads, let G be the event that the fist flip is heads.
