Mathmetics

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

Q521.
From a group of 7 men and 6 women, five persons are to be selected to form a committee so that at least 3 men are there on the committee. In how many ways can it be done ?

1) 565 2) 664
3) 742 4) 756
5)None of these
Answer : 756
Explanation :


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Q522.
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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Q523.
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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Q524.
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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Q525.
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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Q526.
Pipes A and B running together can fill a cistern in 6 min. If B takes 5 min more than A to fill the cistern, then the times in which B will fill the cistern separately will be respectively.

1) 12 min 2) 15 min
3) 18 min 4) 20 min
5)None of these
Answer : 15 min
Explanation :
Let pipe A fills the cistern in x minutes.
Therefore, pipe B will fill the cistern in (x + 5) minutes.
1/x + 1/x+1 = 1/6
        or  x = 10
Hence pipe  B can fill the cistern in 10 +5 = 15 min.
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Q527.
A pipe can fill a cistern in 6 hours. Due to a leak in its bottom it is filled in 7 hours. When the cistern is full, in how much time will it be emptied by the leak ?
1) 40 hours 2) 42 hours
3) 43 hours 4) 45 hours
5)None of these
Answer : 42 hours
Explanation :
Resultant work done by both the pipes in one hour i.e. (1/6 + 1/7) = 1/42
 of cistern.
 The whole cistern will be emptied in 42 hours.
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Q528.
One pipe can fill a tank three times as fast as another pipe. If together the two pipes can fill the tank in 36 minutes, then the slower pipe alone will be able to fill the tank in :

1) 81 min. 2) 108 min.
3) 108 min. 4) 192 min.
5)None of these
Answer : None of these
Explanation :
Let the slower pipe alone will fill the tank in x minutes.
Then faster pipe will fill it in x/3 minutes. then,1/x + 3/x = 1/36  or 4/x = 1/36 
or  x = 144 min. 
       So, the slower pipe can fill the tank in 144 min.

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Q529.
In a partnership deal A puts Rs.2000 for the entire year, B puts Rs. 3000 initially and then increase it to Rs. 4000 at the ned of 4 months and C puts Rs. 4000 initially, but withdraws Rs. 1000 at the end of 9 months. How should they divide a profit of Rs. 8475 at the end of the year ?

1) Rs.1800 2) Rs.3300
3) Rs.3350 4) Rs.3375
5)None of these
Answer : Rs.3300
Explanation :
Calculate the equivalent capital for 1 month for each :
A's capital = Rs. (20002)) = Rs. 24000
B's capital = Rs. (30004 + 40008) = Rs. 44000
C's capital = Rs. (40009 + 30003) = Rs. 45000
Ratio of capitals : 24000 : 44000 : 45000 = 24 : 44 : 45
B's share = Rs .(8475 X 44 )/11 = Rs.3300
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Q530.
A & B entered into partnership with capitals in the ratio of 4 : 5. After 3 months A withdrew 1/4 of his capital and B withdrew 1/5 of his capital. The profit at the end of 10 months was Rs. 760. What is the share of A in that profit ?
1) Rs.300 2) Rs.330
3) Rs.430 4) Rs,560
5)None of these
Answer : Rs.330
Explanation :
Let A invest Rs. 4 & B invest Rs.5. A withdraws (1/4) x 4 = Rs.1
B withdraws (1/5) x 5= Rs. 1
Calculating the equivalent capital for 1 months :
A’s capital = Rs. (43 + 37) = Rs. 33
B’s capital = Rs. (53 + 47) = Rs. 43
Ratio of capitals = 33 : 43
A’s share = Rs.(760 x 30) /76 =Rs.330

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