How many possible 3-letter abbreviations are there that start with the letter b?

This is different from the first one can someone me

Logan wants to know how many skateboards have defective parts. he inspects 20,000 skateboards and keeps track of the number of defects per board. use his probability distribution table to find the expected value for defects on a skateboard.

A. use the formula for continuous compounding with the original example: $1000 invested at 2% for 1 year. record the amount to 5 decimal places. use a calculator. b. compare it to the result using the original compound interest formula with n = 365 calculated to 5 decimal places. which has a larger value? explain.