If the speed of the train is increased by 5 km per hour, it takes 2 hours less in travelling a distance of 300 km. Find the original speed of the train.
Answers
Answer:
25km/hr.
Step-by-step explanation:
Let x km/h be the constant speed of train.
Time taken to cover 300km = 300 / x hrs
Increased speed = x + 5
Time taken to cover 300km when speed is increased to 5 km/h = 300 / x + 5
according to question,
300/x -300/x+5=2
300(x+5) -300x /x(x+5) =2
2(x²+5)=1500
2x²+10=1500
2x²+10-1500=0
2x²+10-1500=0
(divide by 2)
x²+5-750=0
30x-25=-750
30+-25=5
x2 + 30x - 25x - 750 = 0
x(x + 30) - 25(x + 30) = 0
(x + 30) (x - 25) = 0
x=-30 ( this speed was rejected why speed not negative)
hence,
x=25
so, original speed of train =25km/hr.
.
Answer:
let the speed be. x
then according to the question we have ,
300/x+5 - 300/x = 2 taking common 300 and multiplying both sides by 1/300 we get 1/x+5 - 1/x = 2/300 simplyfying the equation we get