SOLUTION: Travel problems I just don't understand. Richard drove his rig at 'x' mph for 3 hours, then increased his speed to (x+15)mph and drove 2 more hours. Wrtie a polynomial that represe

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Question 203169: Travel problems I just don't understand. Richard drove his rig at 'x' mph for 3 hours, then increased his speed to (x+15)mph and drove 2 more hours. Wrtie a polynomial that represents the total distance that he traveled. how much distance did he covered if x=45 mph?
Answer by jejess(7) About Me  (Show Source):
You can put this solution on YOUR website!
Ok first you need to know the equ.s for speed, distance and time.
Speed= distance x time
Distance= speed/time
Time= speed/distance
You need to figure out what distance this guy drove for at each speed and then add the together to find the total distance.
Step one :
Write down eq's for the two speeds but solving for distance
D1=x/3 then D2= (x+15)/2
D1+D2=Total distance
We know x=45 so we sub 45 in for the all the x's and solve
D1=x/3 D2= (x+15)/2
=45/3 = (45+15)/2
=15miles =30 miles
D1+D2= total
15 miles+ 30 miles= 45 miles
Therefore he travled 45 miles
** be sure to include all steps and units for full marks