If 3a - b = 1 and ab = 4, then the value of ((9a2 - b2) is:
The cost price of a chair is 21,800. Later, its cost price becomes 22,100. What is the percentage increase in the cost price of the chair?
\(16\tfrac{5}{6}\%\)
\(16\tfrac{2}{3}\%\)
\(16\tfrac{1}{2}\%\)
\(16\tfrac{1}{3}\%\)