SOLUTION: If I increase my usual driving speed by 10 km/h, I can drive the 255 km to Nashviille in 24 minutes less than usual. How fast do I usually drive?
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Question 67919This question is from textbook Algebra:Structure and Method
: If I increase my usual driving speed by 10 km/h, I can drive the 255 km to Nashviille in 24 minutes less than usual. How fast do I usually drive?
This question is from textbook Algebra:Structure and Method
Answer by checkley71(8403) (Show Source): You can put this solution on YOUR website!
255/x=255/(x+10)+.4
255/x=(255+.4x+4)/(x+10)
255/x=(259+.4x)/(x=10)
255(x+100=x(259+.4x)/(x+10)
255x+2550=259x+.4x^2
.4x^2+4x-2550=0
(.4x-30)(x+85)=0
.4x-30=0
.4x=30
x=30/.4
x=75 km/h is the normal speed
75+10=85 km/h is the faster trip speed
proof
255/75=255/85+.4
3.4+3+.4
3.4=3.4
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