The multiplication sign because "6 teaspoons of flour per pancake (6x) 10 pancakes she want to make (6x10=60) 60 tablespoons of flour!
The answer is D. If you substitute those values for n, you should be able to find that 4 makes the expression equal to 6.
It will be 5 because 4^2+3^2= 16+9=25 and then square root of 25=5
