Latest TCS Aptitude Question SOLUTION: 3. What is where is the number of ways of choosing k items from 28 items? a) 406 * 227 b) 306 * 226 c) 28 * 227 d) 56 * 227

• Placement Papers
• /
• TCS
• /
• Category

TCS Question Papers: TCS Interview Experience(90) TCS Company Profile

(#M40040866) TCS Category question Keep an EYE

3. What is where is the number of ways of choosing k items from 28 items?
a) 406 * 227
b) 306 * 226
c) 28 * 227
d) 56 * 227

Asked In TCS Ritesh Kumar (9 years ago)

Unsolved Read Solution (3)

Is this Puzzle helpful?   (0)   (3) Submit Your Solution

Read Solution (3) :

sakshi samaiya  (9 years ago)

please use correct language while writing questions

Is this solution Helpfull? Yes (4) | No (1)  

KISLAY  (9 years ago)

aSol: A
Consider (1+x)n=C0+C1x+C2x2+.....+Cnxn .......(1)
Differentiating w.r.t x we get
n(1+x)n−1=C1+2C2x+3C3x2+.....+nCnxn−1
Multiplying by x on both sides,
x.n(1+x)n−1=x.C1+2C2x2+3C3x3+.....
Now again differentiating w.r.t to x
n(1+x)n−1+n(n−1)x(1+x)n−2=C0+22C1x+32C2x2+42C3x3.....
Putting x = 1, we get
n(n+1)2n−2=C1+22C2+32C3+42C4
Now substituting n = 28
28(28+1)228−2 = 812.226 = 406.227

Is this solution Helpfull? Yes (2) | No (2)  

soumya  (9 years ago)

write the question properly....

Is this solution Helpfull? Yes | No   

Please Login to Read Solution.