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Refer to the given series and answer the question that follows (all numbers are single-digit numbers only).
What is the sum of the $ 1^{\text{st}}$ digit from the left and the $ 15^{\text{th}}$ digit from the right?
0
6
3
5
3
Count positions from the specified ends carefully: 1st from Left is the start; for 15th from Right, subtract 14 from the total count and move forward, or simply count backwards.
Count positions from the specified ends carefully: 1st from Left is the start; for 15th from Right, subtract 14 from the total count and move forward, or simply count backwards.
Identify 1st digit from the Left
The series starts from the left as: 2, 7, 5, 3... The 1st digit is 2.
Identify 15th digit from the Right
The total number of digits in the series is 30. The 15th digit from the right is the same as the 16th digit from the left (30 - 15 + 1 = 16). Counting from the left: 2(1), 7(2), 5(3), 3(4), 1(5), 5(6), 8(7), 7(8), 7(9), 4(10), 0(11), 6(12), 3(13), 1(14), 2(15), 1(16). The 16th digit is 1.
Calculate the sum
Sum = 1st digit (2) + 15th digit from right (1) = 3.
A: 2 is incorrect as it ignores the 15th digit; B: 5 is a result of miscounting the digits; D: 4 is a result of misidentifying the position.
C is correct because the 1st digit from the left is 2 and the 15th digit from the right is 1, so their sum is 3.
Always verify total length of a series first to avoid off-by-one errors when counting from the right side.
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