Answer: He actually rode 2 miles per hour on his trip
Step-by-step explanation: Maybe unconventional, but express the time it took, then figure the speed.
Time = distance /speed t will represent time, s is the speed: t = 30/s Use the rime it would have taken at the higher speed to create an equation:
t-12 = 30/s+8 replace the y with the 30/s
30/s -12 = 30/s+8
(s)(30/s -12 ) = (s)(30/s+8 ) Cross multiply to cancel denominators
(s-8)(30 -12s) = (s-8)(30s/s+8 ) ==> 30s +240 -12s² -96s =30s Simplify:
(-1)(-12s² -96s +240 ) =0 ==> 12s² +96s -240 divide all by 12
s² + 8s -20 = 0 Factor and solve for s
(s +10)(s -2) =0 s-2=0 S= 2
Proof:
30/2 = 15 hours for original trip at 2mph,
increase speed by 8mph 2 + 8 = 10mph
30 miles at 10mph takes 3 hours; that is 12 hours less than his actual trip.
(Brainilest, please :-)
