Cliff left point A at 8 A.M. walking east at 3 kph. Renz left point A at 9 A.M. walking north at 4 kph.

Question

PLEASE HELP ME TO ANSWER IT I DON'T GET IT. THANKS IN ADVANCE :)

(a) Express the distance between Cliff and Renz as a function of

the time t elapsed since 8 A.M.

(b) How far apart are Cliff and Renz at noon?

(c) At what time are they 20 km apart?

Answer 1

Jirecho

Suppose point A is at (0,0) and the units are km in our coordinate system.

Then at t hrs after 8 am, Cliff will have walked 3t km east, so his coordinates are (3t, 0)

Renz will have walked 4t km north, so his coordinates are (0, 4t)

Distance between them = distance between (3t, 0) and (0, 4t).

Using distance formula this is √ (3t-0)² + (0-4t)² = √ (9t² + 16t²) = √ 25t² = 5t

That's your function

(b) at noon, t=4 . so you can find the distance using the result from (a)

(c) when the distance is 20 km, you can find t, then the clock time

Mike