The answer is 10. If you replace the number letters with the numbers you get 6 + 10 / 2 - 1. Then you follow PEMDAS, so first divide 10 with 2 to get five (6 + 5 - 1). Add 6 and 5 to get 11 and subtract 1 to get the final answer of 10.
Answer: Correct, are you dragging the line across?
E. Populations refers to all members of a group