Question

Tally Marks	Number of Observations
	___________________

Answer 1

Tally mark is a way by which we can count the occurrence of any data by using a small single line to represent one occurrence of data and cutting four lines by a single line to represent a group of five occurrence.

So, here there are two groups of 5 each and 3 more lines which means $5+5+3=13$

so the correct answer is $13$