What is the next number in the series: 12, 15, 21, 30, 42, _?

What is the next number in the series: 12, 15, 21, 30, 42, _?

• A. 50
• B. 52
• C. 55
• D. 57

Answer: (D)

To determine the next number in the series of 12, 15, 21, 30, 42, we first look for a pattern in the differences between consecutive numbers: - The difference between 12 and 15 is 3. - The difference between 15 and 21 is 6. - The difference between 21 and 30 is 9. - The difference between 30 and 42 is 12. Observing these differences more closely, we see they are increasing by 3 each time: 3, 6, 9, 12. Following this pattern, the next difference should be 15 (12 + 3). Now, if we add this next difference of 15 to the last number in the series, 42: 42 + 15 = 57. Thus, the next number in the series is 57. This understanding of how the sequence develops through consistent increments helps clarify why 57 is the correct choice.

To determine the next number in the series of 12, 15, 21, 30, 42, we first look for a pattern in the differences between consecutive numbers:

• The difference between 12 and 15 is 3.

• The difference between 15 and 21 is 6.

• The difference between 21 and 30 is 9.

• The difference between 30 and 42 is 12.

Observing these differences more closely, we see they are increasing by 3 each time: 3, 6, 9, 12. Following this pattern, the next difference should be 15 (12 + 3).

Now, if we add this next difference of 15 to the last number in the series, 42:

42 + 15 = 57.

Thus, the next number in the series is 57. This understanding of how the sequence develops through consistent increments helps clarify why 57 is the correct choice.