Practicing Success
A sum of ₹2,432 amounts to ₹2,681.28 in 2 years at a certain rate per cent per annum, interest compounded yearly. What will be the simple interest (in ₹) on the same sum for 4(3/8)years at double the rate? |
1,276.80 1,094.40 1,064 1,368 |
1,064 |
The Formula that we used here is - Amount = P$(1 \;+\; \frac{R}{100})^t$ 2681.28 = 2432 [ 1 + \(\frac{R}{100}\) ]² \(\frac{2681.28}{2432}\) = [ 1 + \(\frac{R}{100}\) ]² \(\frac{441}{400}\) = [ 1 + \(\frac{R}{100}\) ]² (\(\frac{21}{20}\))² = [ 1 + \(\frac{R}{100}\) ]² On solving , R = 5% Double the rate = 10% Now, Simple interest for 4(3/8) years = \(\frac{2432 ×10× 35 }{100 ×8}\) = \(\frac{2432 × 35 }{10 ×8}\) = Rs. 1064 |