Answer:
The given expression 15:60 can be simplified by dividing both the numerator and denominator by their greatest common factor (GCF), which is 15 in this case. So, 15 divided by 15 is 1 and 60 divided by 15 is 4. Therefore, the simplified form of 15:60 is 1:4.
So, the answer is (b) 1:4.