one car is traveling at 70mph..the second car is 50 miles behind the first car in 2.5 hours..what rate is the second car going

Question

rate x time equals distance

my problem is:

car a is traveling at 70mph car B is 50 miles behind car a in 2.5 hours..what rate is B traveling at?

Answer 1

Hi Karen;

FIRST CAR...70 miles/hour....distance x

SECOND CAR....x miles/hour...distance (x-50)

 

After 2.5 hours, the FIRST CAR is...

distance=(velocity)(time)

s=vt

distance=(70 miles/hour)(2.5 hours)

The unit of hours is in the denominator and numerator.  It cancels...

distance=(70 miles/hour)(2.5 hours)

distance=(70 miles)(2.5)

The only unit remaining is miles.  This is what we want.

distance=175

 

After 2.5 hours, the SECOND CAR is...

(175 miles)-(50 miles)=125 miles

distance=(velocity)(time)

s=vt

s/t=v

(125 miles)/(2.5 hours)=v

The units are miles/hour.  This is what we want...

50 miles/hour=velocity of the second car