SOLUTION: A truck traveled the first 165 miles of a trip at one speed and the last 100 miles at an average speed of 5 miles per hour less. The entire trip took 5 hours. What was the average

Question 809412: A truck traveled the first 165 miles of a trip at one speed and the last 100 miles at an average speed of 5 miles per hour less. The entire trip took 5 hours. What was the average speed for the first part of the trip?
Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!
First Part x mph
Second Part x -5 mph
Total time 5 hours
First Part time 165 / x
Second Part time 100 / ( x -5 )

Time first part + time second part = 5 hours

165 / x + 100 /(x -5 ) = 5
LCD = ( x + 0 )* (x -5 )
multiply the equation by the LCD
we get
165 * (x+ -5 = 5
165 x+ -825 + )+ 100 x = 5 X^2 -25 x
290 x+ -825 = 5 X^2 = 0
5 X^2 -290 x+ 825 = 0
5 X^2+ -290 x+ 825 =
/ 5 0
5 X^2 -290 x+ 825 =
/5
x^2-58x+165=0
factors are -55 & -3
x=55 OR 3
first part 55 mph
second part =50 mph

RELATED QUESTIONS
A truck traveled the first 100 miles of a trip at one speed and the last 135 miles at an... (answered by stanbon,Boreal)

A truck traveled the first 100 miles of a trip at one speed and the last 135 miles at an... (answered by ewatrrr)

A truck traveled the first 80 miles of a trip at one speed and the last 105 miles at an... (answered by josgarithmetic)

A truck traveled the first 90 miles of a trip at one speed and the last 80 miles at an... (answered by mananth)

A truck traveled the first 200 miles of a trip at one speed and the last 225 miles at the (answered by josgarithmetic)

A truck driver traveled at an average speed of 45 miles per hour on a 100-mile trip to... (answered by solver91311)

A truck driver traveled at an average speed of 64 miles per hour on a 200-mile trip to... (answered by richwmiller)

A truck driver traveled at an average speed of 60 miles per hour on a 200-mile trip to... (answered by Alan3354,adamhen894)

A truck driver traveled at an average speed of 64 miles per hour on a 200-mile trip to... (answered by josgarithmetic,Alan3354,ikleyn)