Study the following sequence and then answer the question given below:
9 H 7 Z A 9 2 B C H 3 1 X W V 5 T 4 M 6 0 Q 8 F J.
If every fourth letter/number in the above sequence starting from 7 is eliminated, which of the following will be fifth letter/number to the left of the 12th position from your right?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Z
Number the 25 elements of the sequence from the left, remove the ones the question names, and then count again in the shortened sequence.
Removing every fourth element, starting with 7:
7 is the 3rd element, so the 3rd, 7th, 11th, 15th, 19th and 23rd elements go: 7, 2, 3, V, M, 8.
The sequence left has 19 elements: 9 H Z A 9 B C H 1 X W 5 T 4 6 0 Q F J.
Counting in the new sequence:
12th from the right \(=19-12+1=8\)th from the left \(=\) H
Fifth to the left of it \(=8-5=3\)rd from the left \(=\) Z
The phrase “starting from 7” can also be read with 7 counted as the first of the four, so that the 6th, 10th, 14th, 18th and 22nd elements (9, H, W, 4, Q) go. That leaves 20 elements; the 12th from the right is the 9th from the left (3), and the fifth to the left of it is the 4th, which is again Z. Both readings give the same answer.