Calculate the logarithm to base 9 of 3^-4 * 9² * (81)^-1

In a small village of 500 people, 350 speak the local language while 200 speak pidgin English. What percentage of the population speak both.

Find the tax on an income of N20,000 if no tax is paid on the first N10,000 and tax is paid at N50 in N1000 on the next N5000 and at N55 in N1000 on the remainder