Question

A train travels 360 km at a uniform speed. if speed had been 5 km/hr more, it have taken 1 hour less for the same journey. form the quadratic equation to find the speed of the train.

Answer 1

if v then d=360 with time t .................................. (1)
if (v+5) and d=360 too then time needed is t-1 ............................(2)
(1) says:
360=v*t ...............................(3)
(2) says:
360=(v+5)*(t-1) ....................(4)
Find the quadratic eq from (3) and (4) :)

Answer 2

so it would be 40 km/h right?

Answer 3

Correct :)

Answer 4

yeh because at the end you get two answers- -45 and 40 ... since you cannot have a negative speed it must be 40 XD

Answer 5

let the speed of the train be x km/hr then time rqd to travel 360 =360/x
for the speed of (x+5) km/hr the then time is 360/(x+5)
by the problem 360/x - 360/(x+5) =1
hence 1/x - 1/(x+5) =1/360 or 5/(x(x+5)) =1/360
or the required quadratic is x(x+5)=360*5
or x^2 +5x -1800=0 (reqd quadratic)
hence x^2 +45x -40x-1800=0
or x(x+45) -40(x+45)=0
or(x+45)(x-40)=0
hence x =40 (neglecting -ve speed of -45 )
thus the required speed of the train is 40 km/hr

Answer 6

thank u matricked

Answer 7

welcome

Answer 8

plz help
a two digit num is such that the product of the digit is 12. when 36 is added to the number the digits interchange thier places. find quad eq?