The quantitative data set under consideration has roughly a bell-shaped distribution. Apply the empirical rule to answer the following question. A quantitative data set has a mean of 23 and a standard deviation of 4 . Approximately what percentage of the observations lie between 11 and 35 ?

At the beginning of 1974/75,2 years a man invested #2000 in a bank at 12.5% compound interest, if it degree #650 at the end of each two years to pay his son's school fees, after payment of interest to pay his son's school fees, how much did he have left at the beginning of the 1978/79 school year?