Question

I need help with questions 1,2, and 3. Would gratefully appreciate it (:

Answer 1

Explanation:

(2):

First let's organise the data:

33 miles ... x mph ... 4h - downstream

33 miles ... y mph ... 7h - up the stream

x = 33/4 = 8.25 mph

y = 33/7 = 4.71 mph

(3)

P(x) =
`x^2 - 2x - 3`

To find the amount of key rings sold when the profit is 5000$ we have to equate P(x) with 5, because in the problem the profit of the key rings is displayed in terms of thousands.

`x^2 - 2x - 3 = 5\\x^2 - 2x - 8 = 0\\x_1 = 4, x_2 = -2`

Since the number of keyrings sold has to be positive the only answer is 4 thousand key rings.