Information and Communication Technology - Number System
51. Descending order of 15/16,11/20,13/25 is
- Option : C
- Explanation : ∴ x-y=4 =>x=4+y
and 1/x+1/y=10/21
=1/4+y+1/y=10/21 =>y+4+y/y24y=10/21=> 42y+ 84 = lOy2 + 40y
=> lOy2 - 2y - 84 = 0 => 5y2 -y- 42 = 0
=> 5y2 -15y+ 14y- 42 = 0
=> 5y(y -3) + 14(y - 3) = 0
∴ y = 3
53. If sum of six consecutive odd numbers is 168, then find the largest of these numbers.
- Option : D
- Explanation : Let the odd number be 2x+ 1 Then, 1(2x-5)+ (2x- 3)+ (2x-l) +(2x+ 1)+(2x+3)+(2x+5)=168 => 12x = 168 =>x = 14 :. Largestis 2x+5 = 28+5 = 33
- Option : B
- Explanation : Let the fraction be 5x/7y Now, sum of numerator and denominator = 91 i.e 5x + 8y = 91 => 13x = 91 => x = 7 ∴ Numerator = 35 and denominator = 56 :. Difference of denominator and numerator = 56 - 35 = 21
