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 :

  2. 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.