Question

A large ice floe is floating at a speed of 3 kilometers per hour. A polar bear leaves the floe and swims in the opposite direction at 9 kilometers per hour. How long will it be before the polar bear is 4 kilometers away from the floe?

How do I do this??? My teacher never teaches me!!

Answer 1

ok, so the total distance will be 4 kilometers

remember, distance=speed times time

the polar bear's distance=9km/h times t  or  9t
t is time in hours

the floe's distance =3km/hr times t or 3t

total disatace=polar bear disatnce+floe's distance=9t+3t=12t

so when will this distance eqal 4km?
4=12t
divide both sides by 12
4/12=t
1/3=t
about 20 mins or 1/3 hour