Question

Find the missing number in the given series:
8, 13, 10, 15, 12,_____

• A. 14
• B. 17
• C. 18
• D. 20

Answer 1

The Correct Option is B

The given series is: 8, 13, 10, 15, 12, ______

We need to identify the pattern in the series to find the missing number. 

1. Observe the pattern.
   • Start with the first number: 8
   • The difference between the first and second numbers (13 - 8) is +5.
   • The difference between the second and third numbers (10 - 13) is -3.
   • The difference between the third and fourth numbers (15 - 10) is +5.
   • The difference between the fourth and fifth numbers (12 - 15) is -3.
2. From the differences, observe an alternating pattern: +5, -3, +5, -3.
3. Based on this alternating sequence, the next difference should be +5.
4. Add this calculated difference to the last known number in the series: \(12 + 5 = 17\)

Therefore, the missing number in the series is 17.

Let's verify with reasoning:

• The series follows a pattern of adding 5 and then subtracting 3 repeatedly.
• The given series: 8 (+5) 13 (-3) 10 (+5) 15 (-3) 12 (+5) results in 17.

 

Thus, the correct answer is 17.