<PRE><B>Question 1118168</B>
Two families are traveling by car to a camp 280km away.
 One family leaves 20 minutes ahead of the other family and travels at an average of 40 km/h.
 What would the speed of the second family’s car need to be if the family is to reach the camp at the same time as the first family? 
:
find the time it takes the 1st family to travel 280 km at 40km/h
280/40 = 7hrs
:
let s = speed of the 2nd car to arrive in 7 hrs - 20 min or 6{{{2/3}}} hrs
s * 6{{{2/3}}} = 280
s * {{{20/3}}} = 280
multiply equation by 3
20s = 3 * 280
20s = 840
s = 840/20
s = 42 km/h will make arrive at the same time
:
:
Check: 42 * 6.667 = 280.0</PRE>