Find a rational number halfway in between the two numbers. three sevenths and one tenth

The rational number is : 37/140

Explanation:
The first number given is three sevenths which can be written as 3/7
The second number given is one tenth which can be written as 1/10

Now, we want to get the midpoint between these two numbers. The midpoint can be calculated as follows:
midpoint = (first number + second number) / 2
midpoint = [(3/7) + (1/10)] / 2 
midpoint = 37/140

Hope this helps :)