Just subsitute 8 for n
1/2(8)^2-1/2(8)
1/2(64)-4
32-4
28
D
11 boys and 8 girls because you divide it in half the add 2 and subtract 1. That isn't the wy you are supposed to do it but it works and makes since in my head.
A.) the greatest amount of boxes would probably be 8
B.) the amount of cars would be 5 and the airplanes would be 3
Here is how to work the problems and write the expressions.
Answer:39
Step-by-step explanation:
90-51=39