Mathmetics
ISBT Mathmetics for all banking PO,Clerk,IBPS PO,Railway,SSC,IAS,OAS Exams
Q81. 

1)  4 years  2)  6 years 
3)  8 years  4)  12 years 
5)  None of these 
Answer : 6 years
Explanation :
Explanation :
Mother's age when Prasant's brother was born = 46 years.
Father's age when Prasant's brother was born = (48 + 4) years = 52 years.
Required difference = (52  46) years = 6 years.
View Answer
Q82. 

1)  16 years  2)  18 years 
3)  20 years  4)  24 years 
5)  None of these 
Answer : 20 years
Explanation :
Explanation :
Let, the present ages of Alok and Prakash be x and (60 x) years respectively.
Then, (60  x)  6 = 5(x  6)
54  x = 5x  30
or 6x = 84
or x = 14.
So, Prakash's age after 6 years = (x+ 6) = 20 years.
View Answer
Q83. 

1)  14 years  2)  19 years 
3)  24 years  4)  28 years 
5)  None of these 
Answer : 19 years
Explanation :
Explanation :
Let, B's present age be x years. Then, (48  x) = x
Or 2x = 48.
Or x = 24.
B's age 5 years back (24  5) = 19 years.
View Answer
Q84.  There are 5 men and 3 women to form a committee of 5members where at least 3 men are there. How many way they can be selected ? 
1)  42  2)  45 
3)  46  4)  54 
5)  None of these 
Answer : 46
Explanation : Total ,5 men and 3 women i.e. 8 persons.
Explanation : Total ,5 men and 3 women i.e. 8 persons.
So, 3 men can selected from 5 men.
They can selected in (^{5}C_{3}_{ }x ^{3} C_{2} ) or (^{5}C_{4}_{ }x^{ 3} C_{1} ) or (^{5}C_{5}_{ }x ^{3 }C_{0} )
Total numbers of way to select = [(5 x 4 )/2 x 3 ] +[(5 ) x 3 ] + [(1x 1) ] = 46
View Answer
Q85.  The sum of two numbers is 27 and their H.C.F is 3. If one of the number is lies between 13 to 16, the find the value of the other number ? 
1)  12  2)  15 
3)  18  4)  24 
5)  None of these 
Answer : 12
Explanation : Let, two numbers are 3x and 3y respectively.
Explanation : Let, two numbers are 3x and 3y respectively.
Then, 3x + 3y = 27
or 3 (x + y) = 27
or (x + y) = 27/3 = 9
So, pairs of numbers are 9 = (1,8) , (2,7) , ( 3,6) and (4,5) .
Thus the numbers are 3 x 4 = 12 and 3 x 5 =15
View Answer
Q86. 

1)  Rs.820  2)  Rs.890 
3)  Rs.1020  4)  Rs.1250 
5)  None of these 
Answer : Rs.890
Explanation :
Explanation :
A : B : C = (8,000 x 6) : (4,000 x 8) : (8,000 x 8) = 48 : 32 : 64 = 3 : 2 : 4.
B's share = ( Rs. 4005/9) x 2 = Rs. 890.
View Answer
Q87. 

1)  Rs.1200  2)  Rs.1250 
3)  Rs.1450  4)  Rs.1500 
5)  None of these 
Answer : Rs.1500
Explanation :
Explanation :
Let, the total profit be Rs. 100.
After paying to charity, A's share = (Rs. 95 /5)x 3 = Rs. 57.
If A's share is Rs. 57, total profit = Rs. 100.
If A's share Rs. 855, total profit = ( 855/57) x100 = 1500
View Answer
Q88. 

1)  4 : 5  2)  5 : 4 
3)  3 : 2  4)  Data Inadequate 
5)  None of these 
Answer : 5 : 4
Explanation :
Explanation :
C.P. = S.P.  Profit
or C.P. = 5 1 = 4
or S.P. : C.P. = 5 : 4
View Answer
Q89. 

1)  Rs. 4,250  2)  Rs. 4,500 
3)  Rs. 6,400  4)  Rs. 7200 
5)  None of these 
Answer : Rs. 7200
Explanation :
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.
View Answer
Q90. 

1)  5: 17  2)  1:11 
3)  11:1  4)  2:3 
5)  None of these 
Answer : 11:1
Explanation :
Explanation :
By alligation method :
2.40 3.60
2.50
3.60  2.50 2.50  2.40
= 1.10 10
So, Ratio will be 11 : 1.
View Answer