Find out the missing (?) number and letter.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 61 and L
The numbers and the letters follow separate rules.
The numbers form one series running through the four boxes (bottom-left, bottom-right, top-right, top-left), each number obtained by adding the next prime number:
\(5+3=8\), \(8+5=13\), \(13+7=20\)
\(20+11=31\), \(31+13=44\)
\(44+17=61\), \(61+19=80\)
The letters are paired in each box, and the gap between the two letters of a box grows by one from box to box:
Top-left: A (1) and C (3), a gap of 2
Top-right: C (3) and F (6), a gap of 3
Bottom-right: E (5) and I (9), a gap of 4
Bottom-left: G (7) and a gap of 5 gives L (12)
The first letters A, C, E, G also go up by 2 each time.
