Question 1066378
.
when a bus travels a certain route at an average speed of 40 km/h it arrives one hour late at its destination, 
and when it averages 48 km/h it arrives one hour early.
Q1;What is the length of the journey?
Q2: How fast should the bus travel in order to arrive on the time at its destination？
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<pre>
1.  Let D be the length of the journey.

    Then the time of traveling at the speed of 40 km/h is {{{D/40}}} hours, 

    and the time of traveling at the speed of 48 km/h is {{{D/48}}} hours. 

    According to the condition, the difference {{{D/40 - D/48}}} is 2 hours.
    It gives an equation

    {{{D/40 - D/48}}} = 2.

    To solve it, multiply both sides by 40*48. You will get

    48D - 40D = 2*40*48  --->  8D = 2*40*48  --->  D = 2*40*6 = 840.

    So, the distance is 840 kilometers, and the first question is answered.



2.  Next, the travel time at the speed of 40 km/h is {{{840/40}}} = 21 hours.

    Hence, the regular/normal/scheduled time is 21 - 1 = 20 hours,  and so

    the regular/normal/scheduled speed is 840/20 = 44 km/h.
</pre>

Solved.



Similar problem was solved in the lesson 

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=http://www.algebra.com/algebra/homework/word/travel/How-far-do-you-live-from-school.lesson>How far do you live from school?</A> 

in this site.



Also, you have this free of charge online textbook in ALGEBRA-I in this site

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson>ALGEBRA-I - YOUR ONLINE TEXTBOOK</A>.


The referred lesson is the part of this textbook under the section "<U>Word problems</U>", the topic "<U>Travel and Distance problems</U>".