Select the option that is related to the third number in the same way as the second number is related to the first number.
16 : 248 :: 20 : ?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 390
In a number analogy, find the operation that turns the first number into the second, then apply the same operation to the third number. Here 248 is just below \(16^2=256\), so compare it with the square.
\(16^2=256\), and \(256-248=8\), which is half of 16
So the rule is: square the number and subtract half of it, \(16^2-8=248\)
For 20: \(20^2=400\), and half of 20 is 10
\(400-10=390\)
So the missing number is 390.