Answer:
The formula for distance problems is: distance = rate × time or d = r × t. Things to watch out for: Make sure that you change the units when necessary. For example, if the rate is given in miles per hour and the time is given in minutes then change the units appropriately.
Step-by-step explanation:
Here is an example.
Two cars started from the same point, at 5 am, traveling in opposite directions at 40 and 50 mph respectively. At what time will they be 450 miles apart?
After t hours the distances D1 and D2, in miles per hour, travelled by the two cars are given by
D1 = 40 t and D2 = 50 t
After t hours the distance D separating the two cars is given by
D = D1 + D2 = 40 t + 50 t = 90 t
Distance D will be equal to 450 miles when
D = 90 t = 450 miles
To find the time t for D to be 450 miles, solve the above equation for t to obtain
t = 5 hours.
5 am + 5 hours = 10 am
