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### Mathmetics

ISBT Mathmetics for all banking PO,Clerk,IBPS PO,Railway,SSC,IAS,OAS Exams

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##### A person invested an amount of Rs. 13,900 divided in two different schemes A and B at the simple interest rate of 14% p.a. and 11% p.a. respectively. If the total amount of simple interest earned in 2 years be Rs. 3508, what was the amount invested in Scheme B ?
 1) Rs.6400 2) Rs.6500 3) Rs.7200 4) Rs.7500 5) None of these
Explanation :
Explanation:
Let the sum invested in Scheme A be Rs. x and that in Scheme B be Rs. (13900 - x).
Then, (x x 14 x 2)/100 + ((13900 - x) x 11 x 2) /100= 3508
28x - 22x = 350800 - (13900 x 22)
or 6x = 45000
or x = 7500.
So, sum invested in Scheme B = Rs. (13900 - 7500) = Rs. 6400.
##### A person invested some amount at the rate of 12% simple interest and a certain amount at the rate of 10% simple interest. He received yearly interest of Rs. 130. But if he had interchanged the amounts invested, he would have received Rs.4 more as interest. How much did he invest at 12% simple interest ?
 1) Rs.400 2) Rs.500 3) Rs.700 4) Rs.800 5) None of these
Explanation :
Explanation :
Let the amount invested at 12% be x and the amount invested at 10% be y respectively

x x 12 x 1)/100 +( y x 10 x 1)/100 = 130
1.2x + y = 1300
Similarly, 1.2y + x = 1340
or (1.2x) x 1.2 + 1.2y = 1300 x 1.2
x +1.2y = 1340
or 0.44x = 1560 - 1340 = 220
or x = (220/0.44) - Rs. 500
or y = 1300 - 1.2 x 500 = Rs. 700

##### A person invested some amount at the rate of 12% simple interest and a certain amount at the rate of 10% simple interest. He received yearly interest of Rs. 130. But if he had interchanged the amounts invested, he would have received Rs.4 more as interest. How much did he invest at 12% simple interest ?
 1) Rs.400 2) Rs.500 3) Rs.700 4) Rs.800 5) None of these
Explanation :
Explanation :
Let the amount invested at 12% be x and the amount invested at 10% be y respectively

x x 12 x 1)/100 +( y x 10 x 1)/100 = 130
1.2x + y = 1300
Similarly, 1.2y + x = 1340
or (1.2x) x 1.2 + 1.2y = 1300 x 1.2
x +1.2y = 1340
or 0.44x = 1560 - 1340 = 220
or x = (220/0.44) - Rs. 500
or y = 1300 - 1.2 x 500 = Rs. 700

##### A person divide his capital worth Rs.4332 into three parts in such way their interest after 2,3 and 4 years equal to each other. The rate of interest on these three parts have to be 4% , 7% and 11% per annum, respectively at S.I. What is the difference between the largest and the smallest part of money invested ?
 1) Rs.1860 2) Rs.2052 3) Rs.2268 4) Rs.2468 5) None of these
##### A sum was put at a certain rate of interest for 5 years. Had it been put at 2% higher rate, it would have fetched Rs. 72 more. What is the sum ?
 1) Rs. 4,250 2) Rs. 4,500 3) Rs. 6,400 4) Rs. 7200 5) None of these
Explanation :
We know that Sum = (S.I X 100 )/ R X T
= (Diff. in S.I X 100 ) / Diff. in rate X Time
= (72 X100)/ 2 X 5 =  Rs. 7200.
##### A man lent out Rs.12000 partly at 12% and partly at 15% simple interest . His total income after 2 years was Rs.3300. What is the sum lent at 12% simple interest ?
 1) Rs.4000 2) Rs.5000 3) Rs.6000 4) Rs.7000 5) None of these
Explanation : Let, the sum lent at 12% simple interest is Rs.X.
So, the sum lent at 15% simple interest is (Rs.12000 - x).
Then,
##### What should be the simple interest obtained on an amount of Rs. 67400 at the rate of 8% p.a. after 3 years ?
 1) Rs. 12380 2) Rs.16176 3) Rs.18240 4) Rs.19020 5) None of these
Explanation : SI = [(67400 x 3 x 8) ] /100 = Rs.16176
##### A person deposited Rs.8000 which amounted to Rs.9200 after 3 years at simple interest . Had the interest been 2% more, how much he would get ?
 1) Rs.8,660 2) Rs.9,680 3) Rs.10,620 4) Rs.11,540 5) None of these
Explanation : Given, P = 8,000 , T=3 yrs A= 9200
So, S.I = 9200 - 8000 = 1200
Then , R = (1200 X 100 ) / 8000 X 3 = 5%
After 2% rate increases  , new rate will be 7%.
So, new SI=( 8000 X 3 X 7) / 100 = 1680
Thus, new amount = 8000 + 1680 = 9,680