Latest TCS Aptitude Question SOLUTION: One side of the bottom layer of a triangular pyramid has 12 balls. How many are there in the whole pyramid? Note that the pyramid is equilateral and solid. a) 286 b) 364 c) 504 d)

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(#M40115301) TCS Numerical Ability question Keep an EYE

One side of the bottom layer of a
triangular pyramid has 12 balls. How many
are there in the whole pyramid?
Note that the pyramid is equilateral and
solid.
a) 286 b) 364
c) 504 d) 164

Asked In TCS shikha (9 years ago)

Solved zahid Read Solution (4)

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Read Solution (4) :

zahid  (9 years ago) Best Solution

There are total 364 balls.

As there are 12 balls along one side, it means that there are 12 layers of balls. The top most layer has 1 ball. The second layer has 3 (1+2) balls. The third layer has 6 (1+2+3) balls. The fourth layer has 10 (1+2+3+4) balls. The fifth layer has 15 (1+2+3+4+5) balls. Similarly, there are 21, 28, 36, 45, 55, 66 and 78 balls in the remaining layers.

Hence, the total number of balls are
= 1 + 3 + 6 + 10 + 15 + 21 +28 + 36 + 45 + 55 + 66 + 78
= 364 balls

Is this solution Helpfull? Yes (47) | No (1)  

SREEKANTH THUPILI  (9 years ago)

b)364 answer

Is this solution Helpfull? Yes (3) | No (1)  

sheetal mahamana  (9 years ago)

answer is coming 650 but ther isnt the option...........
coz every mat will contain balls layer by layer,since pyramid is in 3D

12*12+11*11+10*10+9*9+8*8+7*7+6*6+5*5+4*4+3*3+2*2+1=650

Is this solution Helpfull? Yes (1) | No (9)  

akash  (8 years ago)

answer- 364

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