Rs 32000 yield a compound interest of Rs 5044 in 9 months when interest being compounded quarterly.  Find the rate of interest per annum.

20%

Amount = 32000 + 5044 = 37044                            

ATQ,

⇒ Amount = P (1 + \(\frac{R}{100}\))^t

⇒ 37044 = 32000 (1 + \(\frac{R}{100}\))³  

⇒ 9261 = 8000 (1 + \(\frac{R}{100}\))³ 

⇒ (\(\frac{21}{20}\))³ = (1 + \(\frac{R}{100}\))³

⇒ R = \(\frac{1}{20}\) = 5% (quarterly)

⇒ Rate p.a. = 5% × 4 = 20%