Trains Boats and Streams Practice Test 4 with solutions

Question : 1 of 40

Marks: +1, -0

A motorist covers a distance of 39 km in 45 minutes, by moving at a speed of x km/hr for the first 15 minutes, then moving at double the speed for the next 20 minutes and then again moving at his original speed for the rest of journey. Then x is equal to :

31.2
36
40
52

Validate

Solution:

Here, x ×

{15]/{60}+2x × {20}/{60} + x × {10}/{60}

= 39
⇒ 3x + 8x + 2x = 39 ×

{60}/5

⇒ 13x = 39 × 12
∴ x =

{39×12}/{13}

= 36

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