<PRE><B>Question 179158</B>
Distance(d)=Rate(r) times Time(t) or d=rt; r=d/t and t=d/r
Let d=distance travelled at 40 mph
Then (210-d)=distance travelled at 50 mph
time travelling at 40 mph=d/40
time travelling at 50 mph=(210-d)/50
Now we are told that the above two times=5 hr, so:
d/40 +(210-d)/50=5 multiply each term by 200
5d +4(210-d)=1000 get rid of parens
5d+840-4d=1000  subtract 840 from each side
5d+840-840-4d=1000-840  collect like terms
d=160 mi distance travelled at 40 mph
Time travelled at 40 mph=160/40=4 hr----------------------ans
 CK
40*4+50*1=210
210=210


Hope this helps---ptaylor</PRE>