<PRE><B>Question 143737</B>
one way is find out how many minutes is takes to cover 2 mi at 30 mph
:
Time = dist/speed
;
T = 2/30
T = 1/15 hr; 1/15(60) = 4 min, which, as you say, was used up on the 1st mile
:
If you put in a rate equation:
Let x = time required to go down the hill,
:
4 min = 1/15 hr
(x+{{{1/15}}}) = time to cover the two miles
:
Using a rate equation for 30 mph av speed
30 = {{{2/((x+(1/15)))}}}
30(x+{{{1/15))}}}) = 2
30x + 2 = 2
30x = 2 - 2
30x = 0; obviously not a valid solution
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