Select the option that is related to the third number in the same way as the second number is related to the first number.
10 : 30 :: 738 : ?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 1010
Numbers such as 10, 30 and 738 lie just above the cubes 8, 27 and 729, so each is written as a cube plus a small number.
\(10=8+2=2^3+2\)
\(30=27+3=3^3+3\)
So the pair goes from \(n^3+n\) to the same form for the next number, \(n=2\) to \(n=3\)
\(738=729+9=9^3+9\), so here \(n=9\)
The next number is 10: \(10^3+10=1000+10=1010\)
So the missing number is 1010.