3. Find five rational numbers between 3/5 and 4/5.

As per the example above, we know that rational number between 3/5 and 4/5 is (3/5 + 4/5)/2 i.e. (7/5)/2 i.e. 7/10. As, 3/5 < 7/10 < 4/5.

Now,a rational number between 3/5 and 7/10 is (3/5 + 7/10)/2 i.e. (13/10)/2 i.e. 13/20. As, 3/5 < 13/20 <7/10 < 4/5. Similarly, 25/40 , 27/40 , 15/20 are rational numbers between 3/5 and 4/5.

Therefore, five rationals between numbers3/5 and 4/5 are 25/40, 13/20, 27/40, 7/10, 15/20.