Manipal Engineering Manipal Engineering Solved Paper-2015

  • question_answer
    Numbers 1,2,3,...,100 are written down on each of the cards A, B and C. One number is selected at random from each of the cards. The probability that the numbers so selected can be the measures (in cm) of three sides of a right angled triangle, is

    A) \[I={{I}_{0}}\sin \omega t,\]                       

    B) \[{{I}_{0}}=10\]

    C) \[\omega =100\pi \,\text{rad/s}\]                           

    D)  None of these

    Correct Answer: D

    Solution :

    Number of ways of selecting three numbers one on   each   card  \[~=100\times 100\times 100={{100}^{3}}\] We  know  that \[~(2n+1),(2{{n}^{2}}+2n)\]  and \[~(2{{n}^{2}}+2n+1)\]are Pythagorean triplets. \[\therefore \]For n = 1, 2, 3, 4, 5, 6, we get the lengths of three sides of a right angled triangle such that its hypotenuse-is less than or equal.to 100 cm. Now, one Pythagorean triplet (e.g. 3, 4, 5; 5,12,13; etc.) can be chosen in 3! ways. \[\therefore \]Number of ways of selecting 6 Pythagorean triplets \[=6\times 3!\] Hence, required probability \[=\frac{6\times 3!}{{{100}^{3}}}\]


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