b) 1 : 4
c) 2 : 3
d) Data inadequate
Answer: c
Explanation: Let the principal be P and rate of interest be R%.
Required ratio
$$\eqalign{ & = \frac{{ {\frac{{P \times R \times 6}}{{100}}} }}{{ {\frac{{P \times R \times 9}}{{100}}} }} \cr & = \frac{{6PR}}{{9PR}} \cr & = \frac{6}{9} \cr & = 2:3 \cr} $$
Explanation: Let the principal be P and rate of interest be R%.
Required ratio
$$\eqalign{ & = \frac{{ {\frac{{P \times R \times 6}}{{100}}} }}{{ {\frac{{P \times R \times 9}}{{100}}} }} \cr & = \frac{{6PR}}{{9PR}} \cr & = \frac{6}{9} \cr & = 2:3 \cr} $$
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