Hi Shubhra, Balls are identical so we need unordered solution . When two groups get similar number of balls 2x + y = 11 x can vary from 0 to 5 i.e 6 c...

Alternate Approach : We can use Eulers Totient Function here , Sum of coprimes of N below N is = N x Phi(N)/2 So , 100 x Phi(100)/2 = 50 x 40 = 200.

Hello Shubhra ! Remove all even numberswe are left with 50 odd numbers: 1 + 3 + 5 + 7 +..... + 99 = 502 = 2500(Sum of first n odd numbers = n2) Now re...

(x +1) + ( y +1) + ( z +1) = 14 x + y + z = 11 Positive Integral Ordered Solution : (11+3 -1)C( 3-1) = 13C2 = 78 Unorded Solution: (78 - 3 ×...

S sees a shark and reports a shark : 1/8 x 1/6Now, he could have not seen a shark and reported a shark : 5/6 x 7/8so probability = (1/6 x 1/8)/(1/6 x ...

Number of police involved : (135/5 ) x 3 = 81 Ratio of police involved : supporters of Ms. P = 1 : 9 Hence => 81 x 9 = 729.

Alternate Approach : Let the amount of money be 1ooCost of 1 mango => 100/50 = 2 cost of 1 orange => 100/40 = 2.5 After 10% of taxi fare money ...

Hello Nikita , Ratio of mangoes to oranges Gopi can buy is => 4 : 5 Originally he can buy 40 mangoes After 10% of taxi fare he can buy : 40 x 90/10...

Hello Samyak , When blank box is not permitted - use inclusion exclusion . (3^8 - 3C1 × 2^8 + 3C2 × 1^8)/3! . When blank box is permitted : ...

f(x) = ( x - 1)/( x - 2) y =( x - 1 )/(x -2) yx - 2y = x - 1 yx - x = 2y - 1 x ( y-1) = 2y -1 x = (2y -1)/( y-1) f-1(x) = (2x -1 )/( x -1) f-1(4)...

30% of 60 = 18 . Let the team played n matches in a row . so , ( 18 + n)/(60 + n ) = 1/2 n = 24 . Hence,the team won 24 matches in a row .

Hi Nikita , PFA the solution

a = b2 – b a2 – 2a = a (a – 2) = (b2 – b)( b2 – b – 2) = (b -1)(b-2) b (b+1)Product of four consecutive integers is always divisible by 4! i.e = 24 . ...

Hi TarishiWe Know, an + bn is divisible by a + b when n is ODD. an – bn is divisible by a + b when n is EVEN. an – bn is ALWAYS divisible by a – b.So...