Remember that multiples are numbers that can be divided by a number without a remainder so in this case you could add 15 by 15 to find what number in this set is a multiple of 15.
[tex]15+15=30[/tex]
[tex]30+15=45[/tex]
[tex]45+15=60[/tex]
[tex]=60[/tex]
Therefore your answer is "60."
Hope this helps.
