A certain sum amounts to ₹7350 in 2 years and to ₹8575 in 3 years. Find the sum and rate percent. (Campus Recruitment, 2010)
Answer
Answer (as printed):
Explanation
S.I. on ₹7350 for 1 year $=₹(8575-7350)=₹1225$. ∴ Rate $=\left(\frac{100 \times 1225}{7350 \times 1}\right)\%=16\frac{2}{3}\%$. Let the sum be ₹x. Then, $x\left(1+\frac{50}{3 \times 100}\right)^{2}=7350 \Leftrightarrow x \times \frac{7}{6} \times \frac{7}{6}=7350 \Leftrightarrow x=\left(7350 \times \frac{36}{49}\right)=5400$. ∴ Sum $=₹5400$.
Explanation as extracted from the printed page; notation may be imperfect.