EXERCISE 4 (OBJECTIVE TYPE QUESTIONS SOLUTION IN 211 220)

211.       Since ( x – y) + ( y – z) (z – x) / (a² + b²+ c²-ab – b c – ca = a + b + c = (38 + 34 + 28) = 100.

   Given exp. = (3 ( x – y ) *y – z) (z – x ) / 9 (x – y ) ( y –z ( z –x ) = 1/3.

212.       Let total score be X. then, highest score = 3 X / 11.

  Remainder = (x – 3 x / 11 ) = 8 x / 11.next highest score = 3 / 11 of 8x / 11= 24  x/ 121.

  3x /11 – 24x/ 121 = 9   33x – 24 x = 9x 121    9x = 9 x 121     x = 121.

213.       X + 3X  x 0.50 + 14 x 0.10 + 4X   x 0.05 = 50.

  X + 1.5X + 1.40 + 0.2 X = 50    2. 7 X = 48. 60   X = 18.

214.       Suppose their paths cross after x minutes.

   Then, 11 + 57X = 51 – 63x    120 x = 40  x = 1/3.

   Number of floors covered by David in (1/3) min. = (1/3 x 57) = 19.

    So, their paths cross at (11 + 19) i.e. 30 th floor.

215.       N x 50 = (325000 – 300000) = 25000.   N = 500.

216.       Let total number of children be x. then, X x 1/8 x = x/2 x 16    X = 64.

     Number of notebooks = 1/8 x² = (1/8 64 x 64) = 512.

217.       Let number of boys = X. then, number of girls = X.

     Now, 2 (X – 8) = x or X = 16.

     Total number of students = 2x = (2 x 16) = 32.

218.       Let the total number of sweets be (25x + 8).

    Then, (25X + 8) – 22 is divisible by 28.

    (25X – 14) is divisible by 28     X = 14.

     Total number of sweets (25 x 14 x 8) = 358.

219.       Suppose the man works overtime for X hours.

    Now, working hours in 4 weeks overtime for X hours.

    160 x2.40 + x 3.20 = 432   3.20X = 432 – 384 = 48   X = 15.

      Hence, total hours of work = (160 + 15) = 175.

220.   Let number of boys = X. then, number of girls = (100 – X).

     3.60X + 2.40 (100 –X ) = 312   1.20/X = 312  - 240= 72   X = 60.

     Hence, number of girls = (100 –X ) = 40.