Latest TCS Aptitude Question SOLUTION: 1,5,13,27,48,?

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(#M40012762) TCS question solve it Keep an EYE

1,5,13,27,48,?

Asked In TCS The Grim Reaper (11 years ago)

Unsolved Read Solution (13)

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pawan  (11 years ago)

n th term is
Tn = n*(n+2)*(2n+1)/8 when n is even

when n is odd, integer value of term is written in series.
when
n=1,
Tn = 1*3*3/8 = 9/8 = 1 1/8 ... so we take 1 in series
for n=2,
Tn = 2*4*5/8=5
T3 = 3*5*7/8 = 105/8 = 13 1/8
T4 = 4*6*9/8 = 27

..
T6 = 6*8*13/8 = 78

Is this solution Helpfull? Yes (16) | No (9)  

Pargat Pal Singh  (11 years ago)

1, 5, 13, 27, 48, 78, 118

Is this solution Helpfull? Yes (10) | No (7)  

MIR FIROJ ALI  (11 years ago)

1+4*1=5
5+4*2=13
13+7*2=27(even places are repeated)
27+7*3=48
48+10*4=88

Is this solution Helpfull? Yes (7) | No (19)  

Keshav Gupta  (11 years ago)

@pargat pal singh ji: How????

Is this solution Helpfull? Yes (2) | No (3)  

Pargat Pal Singh  (11 years ago)

well explained by Pawan.

Is this solution Helpfull? Yes (2) | No (3)  

Sahil Motwani  (11 years ago)

pawan is this applicable for just this series?
or any other series too

Is this solution Helpfull? Yes (2) | No (3)  

prachitrivedi  (11 years ago)

pis explain

Is this solution Helpfull? Yes (1) | No (2)  

MIR FIROJ ALI  (11 years ago)

5+1+7=13
5+13+9=27
27+48+11=86 (Ans)

Is this solution Helpfull? Yes (1) | No (2)  

Ajay Kumar Gupta  (6 years ago)

Here this series is based on the no. of triangle calculation.
1/8×n(n+2)(2n+1) when n is even

1/8×(n(n+2)(2n+1)-1) when n is odd

Now put n=1(odd) in second formula it will come 1.Put n=3,5 you will get 13,48 resp.

Again put even no. like n=2,4,you will get 5,48 respectively.

So the series will go like this 1,5,13,27,48,78,118,170,235...

Is this solution Helpfull? Yes (1) | No   

Keshav Gupta  (11 years ago)

N(n)=1/8n(n+2)(2n+1) for n even;
1/8[n(n+2)(2n+1)-1] for n odd.
answer is 78.

Is this solution Helpfull? Yes | No (7)  

sandeep  (11 years ago)

pawan or pargat sing .... when shld we use that formula?
applicable to all series??????????

Is this solution Helpfull? Yes | No (1)  

Pratik Sodani  (7 years ago)

78 floor(n*(n+2)*(2*n+1)/8)

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Konathala Mouli Ramananda Chatarayya  (3 years ago)

Ans is 77

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