Since 30% is the same as 0.30, multiply 0.30 by 720 to get 216. Answer is $216. Another way would be knowing that 30% is the same as the two of 30/100 or 3/10. This by multiplying 720 by 3 to get 2160 and then dividing by 10, you'd get the same answer. $216.
Substitute each variable for the coefficient. Remember PEMDAS.
1 5/6 because you have to first find half of 3 which is 1 1/2 then you have to find half of 2/3 which is 1/3 then you have to find a common denominator then add. After that simplest form.