SSC CGL 202011)A certain amount of money at compound interest grows to Rs. 66,550 in 3 years and Rs. 73,205 in 4 years. The rate percent per annum is:
10%
Difference in the interest in 4 years and 3 years = 73205 - 66550 = Rs.6655;
Rate percentage = \({6655\over66550}\times100\) = 10%
SSC CGL 202012)A and B together borrowed a sum of Rs. 51,750 at an interest rate of 7% p.a. compound interest in such a way that to settle the loan, A paid as much amount after three years as paid by B after 4 years from the day of borrowing. The sum (in Rs.) borrowed by B was:
25,000
Let A borrow be Rs.x.
Borrowed by B = 51,750 - x;
Compound interest rate(r) = 7%;
Amount paid by A after 3 year = amount paid by B after 4 year;
Amount = \(principal(1 + r/100)^t\); ⇒ \(x(1 + 7/100)^3 = (51, 750 − x)(1 + 7/100)^4\) ; ⇒ \(x = (51, 750 − x) × 107/100\) ; ⇒ 100x = 5537250 - 107x ; ⇒ x = 5537250/207 = 26750;
Borrowed by B = 51,750 - x = 51,750 - 26750 = 25000
SSC CGL 202013)The compound interest on a certain sum at \(16\frac{2}{3}\)% p.a. for 3 years is Rs. 6,350. What will be the simple interest on the same sum at the same rate for \(5\frac{2}{3}\) years?
Rs. 10,200
Compound interest = 6350; Rate(r) =\( 16\frac{2}{3}\)% = (50/3)%; Time(t) = 3 years;
Compound interest = \( p[(1 + \frac{r}{100})^t - 1]\)
\(6350 = p(1 + \frac{50/3}{100})^3 - 1\) ; ⇒ p = 10800;
Simple interest = \(\frac{prt}{100}\)
r = (50/3)% ; t =\( 5\frac{2}{3}\) = 17/3 ;
Simple interest = \( \frac{10800 \times (50/3) \times (17/3)}{100}\) = Rs.10200