What is the speed of a car traveling 144 km in 90 minutes in kilometers per hour?

Question

Its about physical science.

Answer 1

There are a couple of ways of doing this, but I will just use a proportion.

first off 1 hour = 60 minutes.

 

So 144/90 = x/60 will give me the answer per 60 minutes of miles per hour.

 

cross multiply to get  90x = 8640

divide by 90 to get 96 miles per 60 minutes or 96 mph.

 

Hope this helped.

Answer 2

rate * time = distance, or rt=d
given, t=90 min =1.5 hours and d= 144 km,
r*1.5 = 144, or r= 144/1.5 = 96 km/hour

 

If you don't want to memorize formulas, try to understand the words and see if you can figure something out from that.

A good way to think about this is take the phrase "kilometers per hours" from the question. You are given "144 miles in 90 minutes" and what you need to figure out is "144 km in X hours." To go from 90 min to hours, you can do 90 min * 1hr/60min = 1.5 hr. So you are left with 144 km in 1.5 hrs or 144 km per 1.5 hours. 144/1.5 = 96. 

 

Another way to think about it is using a ratio

 

144km / 1.5hr  =  X km / 1 hr