The number line has steps of 10.
Write out the different points given in the number line:
70, 80, 90, 90, 100, 100, 100, 110, 110, 110, 110, 120, 120, 120, 120, 130, 130, 140
There are 18 points given in the number line. When you are finding the median of a set of points with an even amount of terms, you will have to find the average of the two middle numbers.
To find the two numbers that should be used, add the total amount of terms in the set by 1, then divide by 2:
9.5 is between 9 and 10, so the 9th and 10th terms will be used.
The 9th and 10th terms in this set of points are 110 and 110. Because both numbers are the same, this means that
the median is 110.