Select the option that is related to the third number in the same way as the second number is related to the first number.
4 : 250 :: 6 : ?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 686
250 is not a square or a cube, but half of it is a cube: \(250=2\times125=2\times5^3\), and 5 is one more than 4.
So the rule is: add 1, cube, and double, \(2\times(4+1)^3=2\times125=250\)
For 6: \(6+1=7\), and \(7^3=343\)
\(2\times343=686\)
So the missing number is 686.