OK I don't get this one question on my homework and I do not understand it can you help me with this please

The question is:90 is 60% of what number

Convert the 60% into a fraction.
You then get 60/100 or 3/5

If 3/5 is 90 , What is the whole number.
Take it from here.

First, write 90 over "b". Then an = sign, then put 60 over 100 (60 out of 100%). After that, just cross multiply...