686 barrels left. If I'm not mistaken this should just be simple subtraction
First and third, second can still be simplified.
4*d^(-3)*d^18 = 4*d^(18-3) = 4*d^(15). The trick here is to combine the exponents.
Another way to write this problem would be:
4*d^18
---------- . Here d^18 divided by d^3 results in d^15, so again the final
d^3 answer is 4*d^15.
1 yard is = to 3 feet.
20 yards = to 20 X 3 feet
your answer is 60 feet
