Question 863863: If you pile oranges in a pyramid that has 1 orange in the top layer, 4 in the next layer nine in the third layer, and 16 in the fourth layer, how many oranges will you need to make a pile with 10th layer?
Found 3 solutions by ewatrrr, stanbon, richwmiller:
Answer by ewatrrr(24785)   (Show Source):
Answer by stanbon(75887)  (Show Source):
You can put this solution on YOUR website! If you pile oranges in a pyramid that has 1 orange in the top layer, 4 in the next layer nine in the third layer, and 16 in the fourth layer, how many oranges will you need to make a pile with 10th layer?
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Sum = 1 + 4 + 9 + 16 + ... + 100
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Sum = (n(n+1)(2n+1)/6
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Ans = [10*11*21)/6 = 770
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Cheers,
Stan H.
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Answer by richwmiller(17219)  (Show Source):
You can put this solution on YOUR website! This is neither arithmetic nor geometric progression
Tn=n^2
1,4,9,16,25,36,49,64,81,100
The tenth layer will have 100 oranges
for a total of 385 oranges in the 10 layer display
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