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(#M40025578) TCS Numerical Ability question numbers Keep an EYE

The sequence 1,2,3,-4,5,6. Find the average and sum of first 200 numbers.

Asked In TCS kayal (10 years ago)

Unsolved Read Solution (6)

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Read Solution (6) :

amit   (10 years ago)

1 + 2 + 3 + (-4) + 5 + 6 + 7 + (-8) + 9 + 10 + 11 + (-12) + 13 + ........... + 198 + 199 + (-200)

= 1 +2 + 3 +5 + 6 + 7 + 9 + 10 + ........... + 198 + 199 - ( 4+ 8 + 12 + ........ + 200)

= 1 + 2 + 3 + 5 + 6 + 7 + ... + 199 - ( 4+ 8 + ... + 200) + ( 4 + 8 + 12 + .... + 200 ) - ( 4 + 8 + 12 + .... + 200)

( adding and subtracting the series of 4 to 200 )

= 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + .... + 199 + 200 - 2 ( 4 + 8 + 12 + .... + 200)

= 1 + 2 + 3 + ..... + 200 - 8 ( 1 + 2 + ..... + 50)

= [200*201]/ 2 - 8*[ 50*51]/2

= 20100 - 10200

= 9900

Sum of the series = 9900

Average = 9900/200 = 49.5

Is this solution Helpfull? Yes (36) | No (4)  

padmapriya  (10 years ago)

sequence= 1,2,3,-4,5,6.
so we can form 198 term(row),
199th is again 1, 200th term is 2..
so 1,2 can be 34 times in 200..
3,-4,5,6 can be 33 times in the 200..
sum=(1*34)+(2*34)+(3*33)+(-4*33)+(5*33)+(6*33)=432..
hence there are 200 numbers..
avg=432/200 =2.16...
the answer will be 2.16

Is this solution Helpfull? Yes (28) | No (7)  

poonam  (10 years ago)

in the sequence 1->>34 times
2->>34times
3->>33times
-4-->>33times
5-->> 33 times
6-->>33times

so average will be (33(1+2+3-4+5+6) +1+2) / 200
answer is : 2.16 ans

Is this solution Helpfull? Yes (5) | No (8)  

pawanpreet  (10 years ago)

plz explain..can't understand...how 34 or 33 times

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Surabhi  (10 years ago)

z 49.5 z d ans?

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

ashish gupta  (10 years ago)

sum=39600 avg=198

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

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