First you need to change them to improper fractions.
3 1/2 + 1 2/5
3x2=6+1= 7/2 now do same for 1 2/5 5x1=5+2=7/5 now find LCD for both fractions which is 10 so now the fractions become 35/10 + 14/10=add 35+14=49/10 now divide to turn back into a mixed number 4 9/10 is your answer