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### Mathmetics

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

##### What is the sum of two consecutive even numbers, the difference of whose squares is 84  ?
 1) 34 2) 38 3) 42 4) 46 5) None of these
Explanation : Let the numbers be x and x + 2.
Then, (x + 2)2 - x2 = 84
or 4x + 4 = 84   or  4x = 80
or x = 20. The required sum = x + (x + 2) = 2x + 2 = 42. View Answer
##### The product of two numbers is 9375 and the quotient, when the larger one is divided by the smaller, is 15. The sum of the numbers is:
 1) 380 2) 395 3) 400 4) 425 5) None of these
Explanation : Let the numbers be x and y.
Then, xy = 9375 and     x/y  = 15.
X = 15y
So, y x 15y = 15y2 = 9375
or y2 = 625.          y = 25.
x = 15y = (15 x 25) = 375.
Thus, Sum of the numbers = x + y = 375 + 25 = 400. View Answer
##### The sum of the squares of three numbers is 138, while the sum of their products taken two at a time is 131. Their sum is:
 1) 20 2) 30 3) 40 4) 24 5) None of these
Explanation : Let the numbers be x, y and z.
Then, x2 + y2 + z2 = 138   and  (xy + yz + zx) = 131.
or  (x + y + z)2 = x2 + y2 + z2 + 2(xy + yz + zx)  = 138 + 2 x 131 = 400.
or  (x + y + z) = 20. View Answer
##### The sum of the digits of a two-digit number is 15 and the difference between the digits is 3. What is the two-digit number ?
 1) 69 2) 78 3) 96 4) D.I 5) None of these
Explanation :   Let the ten's digit be x and unit's digit be y.
Then, x + y = 15 and x - y = 3   or   y - x = 3.
Solving x + y = 15   and   x - y = 3, we get: x = 9, y = 6.
Solving x + y = 15   and   y - x = 3, we get: x = 6, y = 9.
So, the number is either 96 or 69.
Hence, the number cannot be determined. View Answer
##### The difference between a two-digit number and the number obtained by interchanging the positions of its digits is 36. What is the difference between the two digits of that number?
 1) 3 2) 4 3) 9 4) D.I 5) None of these
Explanation : Let the ten's digit be x and unit's digit be y.
Then, (10x + y) - (10y + x) = 36
or 9(x - y) = 36   or x - y = 4. View Answer
##### Find a positive number which when increased by 17 is equal to 60 times the reciprocal of the number.
 1) 3 2) 10 3) 17 4) 20 5) None of these
Explanation :   Let the number be x.
Then, x + 17 =  60/x       or   x2 + 17x - 60 = 0
or  (x + 20) (x - 3) = 0    or    x = 3. View Answer
##### On dividing a number by 56, we get 29 as remainder. On dividing the same number by 8, what will be the remainder ?
 1) 4 2) 5 3) 6 4) 7 5) None of these
Explanation : Dividend = ( 56 x  Q ) + 29         (Q = Quotient )
Dividend = ( 87 x Q ) + (8 x 3) +5
All Parts are divisible by 8 except 5.
So,5 should be the reminder. View Answer
##### The difference of two numbers is 1365. On dividing the larger number by the smaller, we get 6 as quotient and the 15 as remainder. What is the smaller number ?
 1) 240 2) 270 3) 295 4) 360 5) None of these
Explanation : Let the smaller number be x.
Then larger number = (x + 1365).
x + 1365 = 6x + 15
5x = 1350   or  x = 270
Thus , Smaller number = 270. View Answer
##### Which one of the following numbers is exactly divisible by 11 ?
 1) 235641 2) 245642 3) 315624 4) 415624 5) None of these View Answer View Answer