The Cunninghams are moving across the country (r)(t)=d

Question

The Cunninghams are moving across the country. Mr. Cunningham leaves 2.5 hours before Mrs. Cunningham. If he averages 40 mph and she averages 65 mph, how long will it take Mrs. Cunningham to overtake Mr. Cunningham?

Answer 1

65t = 40(t+2.5)

65t=40t+100

25t=200

t=4 Hours 

Answer 2

Hi Megan,

 

Suppose Mrs. C overtakes Mr. C after 'x' hrs. after Mr. C had started the journey,

 

the distance traveled by Mr. C till then : 40x miles

 

Mrs. C starts off after 2.5 hrs, so distance traveled by her in (x-2.5) hrs : 65(x-2.5) miles

 

Now these 2 distances have to be equal 

 

40x=65(x-2.5)

 

40x = 65x - 162.5

 

65x-40x = 162.5

 

x= 162.5/25

 

x = 6.5 hrs

 

That means after 6.5 hrs after Mr. C starts the journey Mrs. C's vehicle will meet his vehicle and then she may overtake

 

I think this will help .........