How to multiply decimals?

3.9 ÷ 38.22

Anormally distributed data set has a mean of 176.3 and a standard deviation of 4.2. what is the approximate z-score for the data value of 167.9? 2.00 −2.00 8.4 −8.4

If $740 is invested at an interest rate of 11% per year and is compounded continuously, how much will the investment be worth in 7 years? use the continuous compound interest formula a = pert.

In a two-digit number the units' digit is 7 more than the tens' digit. the number with digits reversed is three times as large as the sum of the original number and the two digits. find the number.