Speed distance time?

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2 Answers
Feb 17, 2018

If they start moving towards each other simultaneously, they will meet after # 1# hour.

Explanation:

If they meet at a distance#x# from the truck side,

Distance covered by truck will be :

Distance = #x# = speed x time = #145/2.5 xx t #

#=> x = 58t#------(1)

Distance covered by car will be :

distance = #145-x# = 1.5 times speed of truck x time=

#145-x#= #1.5 xx 145/2.5 xx t#

#=> -x = (145 xx1.5)/2.5 xx t - 145#

#=>-x = 87 t -145#

# =>x = 145 -87t#----(2)

equating (1) and(2):

#58 xx t = 145- 87 t#

# 87t +58t = 145#

#=> 145 t =145#

#=> t =1# hour.

Feb 17, 2018

One hour.

Explanation:

Using the fact that #d=rt#, we first solve for the speed of the truck.

#145=2.5r#
#58=r#

The rate of the truck is 58 miles per hour.

Since the car is 1.5 times faster than the truck, the speed of the truck is #1.5×58# or #87# miles per hour.

Now, if the truck and the car are coming towards each other, then it is the same as combining their speed.

Therefore, #145=(58+87)t#

#145=145t#
#t=1#

It takes one hour.