Answer: 24.63
Step-by-step explanation: To find the area of a circle you square the radius (by 2) and then multiply it by pie.
Plug n = 1 into the expression 20-9n and we get
20-9n = 20-9*1 = 20-9 = 11
So 11 is the first term of the series that we add up. Therefore the answer must be choice C, which has 11 listed as the first term added
D will be the answer shifter left 1 point

is the proportion of tires that are defective so

so we would expect around 1600 tires to be defective