InterviewSolution
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InterviewSolution
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A man travels from A to B at a speed of x km/hr. He then rests at B for x hours. He then travels from B to C at a speed of 2x km/hr and rests for 2x hours. He moves further to D at a speed twice as that between B and C. He thus reaches D in 16 hours. If the distance A – B, B – C and C – D are all equal to 12 km, then what could be the time for which he rested at B? |
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Answer» Total time taken from A to D = \(\frac{12}{x}+x+\frac{12}{2x}+2x+\frac{12}{4x}\) Given, \(\frac{21}{x}+3x=16\) ⇒ 21 + 3x2 – 16x = 0 ⇒ 3x2 – 16x + 21 = 0 ⇒ 3x2 – 9x – 7x + 21 = 0 ⇒3x(x – 3) – 7(x – 3) = 0 ⇒ (x – 3) (3x – 7) = 0 ⇒ x = 3 or x = \(\frac73\) ∴ x = 3 hrs or \(\frac73\) hrs. |
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