7.3
To convert 310% to decimal divide by 100: 310% ÷ 100 = 3.1
310.0 that's to one decimal place but you can write it as 310.000000000000000000 . . .
4 3/10 = 4.3
When you write the decimal number '7' in Base-2 (binary), you write '0111'.
7 tenths as a decimal is 0.7
7/100 = 0.07 as a decimal
310% = 3.10 or 3.1
4/310 = 0.0129
It is 310, exactly as in the question.
7/2 as a decimal is 3.5
7
3 + 310 = 313.