SIMPLE INTEREST

Ans .

8500

1. Explanation :

   P= Rs.6800,R= 50/3%p.a and T =9/12years=3/4 years.

   S.I=(P*R*T)/100=Rs(68,000*(50/3)*(3/4)*(1/100))=Rs.8500

Ans .

37.50

1. Explanation :

Time = (24+31+18)days = 73 days = 73/365 years = 1/5 years. P = Rs.3000 and R = 6 1/4%p.a = 25/4%p.a

S.I. = Rs.(3,000*(25/4)*(1/5)*(1/100))= Rs.37.50.

Ans .

1625

1. Explanation :

   Let sum be Rs. x then , S.I.=Rs.(x\(\frac{27}{2}\)*4*(1/100) ) = Rs.27x/50

   amount = (Rs. x+\(\frac{27x}{50}\) = \(\frac{77x}{50}\)

   \(\frac{77x}{50}\) = 2502.50

   x = \( \frac{2502.50x50}{70}\)

   = 1625 Hence , sum = Rs.1625.

Ans .

992

1. Explanation :

   S.l. = Rs. (920 - 800) = Rs. 120; p = Rs. 800, T = 3 yrs.

   R = (\(\frac{100 x 120}{(800*3)}\) ) % = 5%. New rate = (5 + 3)% = 8%. New S.l. = Rs. \(\frac{(800*8*3)}{100}\) = Rs. 192.

   New amount = Rs.(800+192) = Rs. 992.

Ans .

12,000

1. Explanation :

   Let the sum borrowed be x.

   Then,\(\frac{(x*2*6)}{100}\) + /(/frac{(x*9*3)}{100}\) + \(\frac{(x*14*4)}{100}\)= 11400

   (3x/25 + 27x/100 + 14x / 25) = 11400

   95x/100 = 11400 ? x = (11400*100)/95 = 12000.

   Hence , sum borrowed = Rs.12,000.

Ans .

208 ,13%

1. Explanation :

   S.I. for 1 1/2 years = Rs.(1164-1008) = Rs.156.

   S.l. for 2 years = Rs.(156*(2/3)*2)=Rs.208

   Principal = Rs. (1008 - 208) = Rs. 800.

   Now, P = 800, T = 2 and S.l. = 208.

   Rate=(100* 208)/(800*2)% = 13

Ans .

6\(\frac{1}{4}\)% p.a

1. Explanation :

   Let principal = P. Then, S.l. = P and T = 16 yrs.

   Rate = (100 x P)/(P*16)% = 6\(\frac{1}{4}\)% p.a.

Ans .

6\(\frac{2}{3}\)% p.a., 6 yrs 8 months

1. Explanation :

   Let sum = Rs. x. Then, S.l. = Rs. 4x/9

   Let rate = R% and time = R year.

   Then, (x*R*R)/100=4x/9 or \(R^2\) =400/9 or R = 20/3 = 6 2/3.

   Rate = 6\(\frac{2}{3}\) % and Time = 6\(\frac{2}{3}\) = 6 years 8 months.

Ans .

800

1. Explanation :

   Let the sum be Rs. x Then,\(\frac{x*10*7}{100*2}\) - \(\frac{x*12*5}{100*2}\) = 40

   \(\frac{7x}{20}\)-\(\frac{3x}{10}\)=40

   x = (40 * 20) = 800.

   Hence, the sum is Rs. 800.

Ans .

6000

1. Explanation :

   . Let sum = P and original rate = R.

   Then, [ \(\frac{(P*(R+2)*3)}{100}\)]-[\(\frac{(P*R*3)}{100}\)] = 360.

   3PR + 6P - 3PR = 36000

   6P=36000

   P=6000

   Hence, sum = Rs. 6000

Ans .

325

1. Explanation :

   .Let each Instalment be Rs. x

   Then, ( x+ \(\frac{x*12*1}{100}\) + x\(\frac{(x*12*2)}{100}\) + x = 1092

   ((28x/25) + (31x/25) + x) = 1092

   (28x+31x+25x)=(1092*25)

   x= (1092*25)/84 = Rs.325. Each instalment = Rs. 325.

Ans .

650 ,900

1. Explanation :

   Let the sum lent at 8% be Rs. x and that at 6% be Rs. (1550 - x).

   \(\frac{x*8*1}{100}\) + \(\frac{(1550-x)*6*1}{100}\)=106

   8x + 9300-6x=10600

   2x = 1300 x = 650.

   Money lent at 8% = Rs. 650. Money lent at 6% = Rs. (1550 - 650) = Rs. 900.