Select the option that will replace the question mark so that all three pairs are related in the same way.
12 : 55 :: 19 : ? :: 27 : 115
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 83
Both complete pairs follow one rule of the form (a number) × n + (a number). Find it from the two complete pairs, then use it for 19.
From 12 to 27 the first number goes up by 15, and the second number goes up by \(115-55=60\)
\(60\div15=4\), so the second number is 4 times the first plus something
\(4\times12=48\), and \(55-48=7\), so the rule is \(4n+7\)
Check: \(4\times27+7=108+7=115\)
For 19: \(4\times19+7=76+7=83\)
So the missing number is 83.