Mathmetics

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

Q21.
A person invested Rs.5000 for two years. For the first year, the rate of interest was 7% and the second year it was 8.5%. How much interest did he earn at the end of the two year period ?
1) Rs.805.75 2) Rs.804.75
3) Rs.810 4) Rs.850
5)None of these
Answer : Rs.804.75
Explanation :
Interest at the end of the first year + Interest at the end of the second year
        = Total interest at the end of the two year period is
= ( 5000 x 1 x7) /100 + (5350 x 1 x 8.5 ) /100 = 350 + 454.75 = Rs. 804.75 
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Q22.
If the interest on Rs. 800 be more than the interest on Rs. 400 by Rs. 40 in 2 years, then the rate of interest per annum is :
1) 5% 2) 6%
3) 5.5% 4) 7%
5)None of these
Answer : 5%
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Q23.
A sum fetched a total simple interest of Rs. 4016.25 at the rate of 9 p.c.p.a. in 5 years. What is the sum ?

1) Rs. 4462.50 2) Rs. 8032.50
3) Rs. 8900 4) Rs. 8925
5)None of these
Answer : Rs. 8925
Explanation :
Principal = (100 x 4016.25 ) / ( 9 x 5) = Rs. 8925.

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Q24.
A sum of money at simple interest amounts to Rs. 815 in 3 years and to Rs. 854 in 4 years. The sum is:
1) Rs. 650 2) Rs. 690
3) Rs. 698 4) Rs. 700
5)None of these
Answer : Rs. 698
Explanation :
S.I. for 1 year = Rs. (854 - 815) = Rs. 39.
S.I. for 3 years = Rs.(39 x 3) = Rs. 117.
Principal = Rs. (815 - 117) = Rs. 698.
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Q25.
A sum of Rs. 1550 is lent out into two parts, one at 8% and another one at 6%. If the total annual income is Rs. 106, find the money lent at each rate ?     
1) Rs. 800 2) Rs. 900
3) Rs. 1100 4) Rs. 870
5)None of these
Answer : Rs. 900
Explanation :
Let the sum lent at 8% be Rs. x and that at 6% be 
Rs. (1550 - x).
        or (X x 8 x 1/100 ) + [ {(1500- X) x 6 x 1}/ 100 ] = 106
or 8 x + 9300 - 6 x = 10600
or 2 x = 1300 
or x = 650
Money lent at 8% = Rs.650. 
Money lent at 6% = Rs(1550 - 650) = Rs. 900

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Q26.
A sum was put at S.I. at certain rate for 5 years. Had it been put at 4% higher rate, it would have fetched Rs. 60 more. What was the sum ?
1) Rs.280 2) Rs.300
3) Rs.320 4) Rs.400
5)None of these
Answer : Rs.300
Explanation :
Let Principal =P, Rate of Interest = R
Given, T = 5  So, (P x 5 x R) / 100 
Now new rate of interest =( R+ 4) %
So, S.I. =  {P  x 5 x (R+ 5%) } / 100 
Then,  {P  x 5 x (R+ 5%) } / 100 - (P x 5 x R) / 100  = 60
 or P /60 = 5   or  P= Rs. 300
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