Trains Boats and Streams Practice Test 1 with solutions

Question : 33 of 40

Marks: +1, -0

A train covers a distance of 720 km at a speed of x km. However, if the speed is increased by 30 km per hour, then it will take 2 hour less to cover the same distance. What is the value of ‘x’?

120 km/hour
110 km/hour
100 km/hour
90 km/hour
None of these

Validate

Solution:

New speed of the train = x + 30
According to the question,

{720}/x-{720}/{x+30}

= 2

{x+30-x}/{x^2+30x}

2/{720}

x^2

+ 30x - 10,800 = 0

x^2

+ 120x - 90x - 10,800 = 0
(x + 120) (x - 90) = 0
x = 90 km/hour

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