Which number will follow next in the given series? 3, 16, 29, 42, ?

The correct option is 55.

To find the next number in the given series, we need to determine the underlying pattern by analyzing the differences between consecutive terms.

Let's calculate the difference between each adjacent pair of numbers in the series: 3, 16, 29, 42, ...

First difference:
$$16-3=13$$

Second difference:
$$29-16=13$$

Third difference:
$$42-29=13$$

Since the difference between consecutive terms is consistently 13, this is an arithmetic progression with a common difference of 13.

To find the next number in the series, we simply add 13 to the last given term (42):
$$42+13=55$$

Thus, the next number in the series is 55.