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Find the average of cubes of first 49 positive integers

September 7, 2022 by Prabhat

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Find the average of cubes of first 49 positive integers.

A. 30625
B. 1225
C. 30125
D. 6235

Answer: Option A

Here is complete explanation of Find the average of cubes of first 49 positive integers .

Solution(By ExamCraze Team)

Sum of cubes of first n positive consecutive numbers is $$ = frac{{{{left( {nleft( {n + 1} right)} right)}^2}}}{4}$$
Average
$$ = frac{{{{left( {nleft( {n + 1} right)} right)}^2}}}{4}$$
$$eqalign{ & Rightarrow n = 49 cr & Rightarrow frac{{49{{left( {50} right)}^2}}}{4} cr & Rightarrow 30625 cr} $$