Answer
See below.
Work Step by Step
a) Using the formula the equation is: $233=215.3(1+0.01r)^5\\\frac{233}{215.3}=(1+0.01r)^5\\\sqrt[5] {\frac{233}{215.3}}=1+0.01r\\\sqrt[5] {\frac{233}{215.3}}-1=0.01r\\r=100(\sqrt[5] {\frac{233}{215.3}}-1)\approx1.59$
b) Using the formula the equation is: $300=215.3(1+0.01\cdot1.59)^n\\\frac{300}{215.3}=(1+0.01\cdot1.59)^n\\n=\log_{1+0.01\cdot1.59}\frac{300}{215.3}\approx21.03$
