Question

Challenge The price of Stock A at 9 A.M. was $15.52. Since then, the price has been increasing at the rate of $0.13 each hour. At noon the price of Stock B was

$16.02. It begins to decrease at the rate of $0.11 each hour. If the two rates continue, in how many hours will the prices of the two stocks be the same?
In about I hours, the prices of the two stocks will be the same.
(Round to the nearest tenth as needed.)

Answer 1

Answer: 6 1/6 hours after 9 am, or 3 1/6 hours after noon

Explanation:

If we count time (x) in hours after 9 am, the stock prices will be ...

A = 16.15 +0.06x

B = 16.90 -0.12(x -3)

The value of x when A = B can be found from ...

A = B

16.15 +0.06x = 16.90 -0.12(x -3)

0.18x = 1.11 . . . . . . . . add 0.12x-16.15

x = 6.16666...(repeating) = 6 1/6

6 1/6 hours after 9 am, the prices will be the same. That is 3 1/6 hours after noon.

_____

The attached graph shows the time as military time: 15.167. That's 3:10 pm, or 6 1/6 hours after 9 am.