You can easily divide fractions by whole numbers by dividing the denominator, or bottom part of the fraction, by the whole number.

4. (a) 3 ÷ 3/5 = 3/15
To answer this, divide the denominator (5) by 3. So you get 15. The numerator stays the same. So the answer for that one is 3/15.

I won’t answer it all so you can learn. It’s fun, actually. Keep up the good work!