Answer: 7/10
Step-by-step explanation: To add these two fractions together, we start by finding their common denominator.
The common denominator for 10 and 5 will be the least common multiple of 10 and 5 which is 10.
Since 10 already has a 10 in the denominator, it stays the same.
We multiply top and bottom of our second fraction by 2 and we get 4/10.
Now we are adding like fractions so we simply add across the numerators and keep the same denominator.
So, 3/10 + 4/10 = 7/10.
Therefore, 3/10 + 2/5 = 7/10.