HELP PLS Find the formula for the nth term of the sequence below.

20, −10, 5, −2.5, ...

a)an=−12⋅20nA sub n is equal to negative 1 half times 20 to the n th power

b)an=−12⋅20n−1A sub n is equal to negative 1 half times 20 raised to the n minus 1 power

c)an=20⋅(−12)nA sub n is equal to 20 times open paren negative 1 half close paren to the n th power

d)an=20⋅(−12)n−1

Lisa has three classes that each last 50 minutes. what is the total number of minutes of the three classes

Apiling for a high-rise building is pushed by two bulldozers at exactly the same time. one bulldozer exerts a force of 1250 pounds in a westerly direction. the other bulldozer pushes the piling with a force of 2650 pounds in a northerly direction. what is the direction of the resulting force upon the piling, to the nearest degree? a. 65 n of w b. 25 n of w c. 45 n of w d. 35 n of w

Abicycle training wheel has a radius of 3 inches. the bicycle wheel has a radius of 10 inches.approximately how much smaller, in square inches and rounded to the nearest hundredth, is the area of the training wheel than the area of the regular wheel? *