<PRE><B>Question 154741</B>
One morning, John drove 5 hours before stopping to eat. After lunch, he 
increased his speed by 10 mph. If he completed a 430-mile trip in 8 hours of 
driving time, how fast did he drive in the morning?
:
Let s = his speed in the morning
then
(s+10) = his speed in the afternoon
;
A total of 8 hrs driving time, if he drove 5 hrs in the morning,
He drove 3 hrs in the afternoon
:
Write a distance equation: Dist = time * speed
:
Morning miles + afternoon miles = 430 miles
5s + 3(s+10) = 430
;
5s + 3s + 30 = 430
:
8s = 430 - 30
s = {{{400/8}}}
s = 50 mph in the morning
:
:
Check solution by finding the distance at the two speeds:
5(50) + 3(60) =
250 + 180 = 430
</PRE>