﻿ Quantitative aptitude Question for all banking Bank PO,Clerk,IBPS PO,Railway,SSC,PSUs,IAS,OAS ,C-SAT Exams ﻿

### Mathmetics

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

##### The L.C.M of two numbers is 45 times their H.C.F. If one of the number is 125 and the sum of H.C.F and L.C.M is 1150, the other number is -
 1) 215 2) 220 3) 225 4) 235 5) None of these
Explanation : Given that, 45 H.C.F = L.C.M   and
H.C.F + L.C.M = 1150
or H.C.F + 45 H.C.F = 1150
or 46 H.C.F = 1150
or H.C.F = 1150/46 =25
So, L.C.M = 25 X 45 = 1125
Now, we can get 125 X x = 25 X 1125
or   x =  (25 X 1125) /125 = 225

##### What will be the least number which when doubled will be exactly divisible by 12, 18, 21 and 30 ?
 1) 196 2) 630 3) 1260 4) 2520 5) None of these
Explanation :
L.C.M. of 12, 18, 21 30
= 1260.
So, required number = (1260 ÷ 2)   = 630.
##### What is the least number which when divided by 5, 6 , 7 and 8 leaves a remainder 3, but when divided by 9 leaves no remainder ?
 1) 1677 2) 1683 3) 2523 4) 3363 5) None of these
Explanation :
L.C.M. of 5, 6, 7, 8 = 840.
Required number is of the form 840k + 3
Least value of k for which (840k + 3) is divisible by 9 is k = 2.
Required number = (840 x 2 + 3) = 1683.
##### The sum of two numbers is 55 and the H.C.F. and L.C.M. of these numbers are 5 and 120 respectively. What should be the sum of the reciprocals of the numbers ?
 1) 55/601 2) 12/55 3) 11/120 4) 11/112 5) None of these
Explanation :
##### The H.C.F. of two numbers is 11 and their L.C.M. is 7700. If one of the numbers is 275, then the other is:
 1) 279 2) 283 3) 308 4) 318 5) None of these
Explanation : We know that H.C.F x L.C.M = Product of two numbers
So,other number = (11 x 7700)/275 = 308.
##### The least number which when divided by 5, 6 , 7 and 8 leaves a remainder 3, but when divided by 9 leaves no remainder, is:
 1) 1677 2) 1683 3) 2523 4) 3363 5) None of these
Explanation :
L.C.M. of 5, 6, 7, 8 = 840.
Required number is of the form 840k + 3
Least value of k for which (840k + 3) is divisible by 9 is k = 2.
Required number = (840 x 2 + 3) = 1683.
##### What will be the least number which when doubled will be exactly divisible by 12, 18, 21 and 30  ?
 1) 196 2) 630 3) 1260 4) 2520 5) None of these
Explanation :
L.C.M. of 12, 18, 21 30 = 1260.
Required number = (1260 ÷ 2) = 630.

##### The product of two numbers is 2028 and their H.C.F. is 13. The number of such pairs is:
 1) 1 2) 2 3) 3 4) 4 5) None of these
Explanation :
Let the numbers 13a and 13b.
Then, 13a x 13b = 2028
ab = 12.
Now, the co-primes with product 12 are (1, 12) and (3, 4).
So, the required numbers are (13 x 1, 13 x 12) and
(13 x 3, 13 x 4).
Clearly, there are 2 such pairs.
##### The product of two numbers is 120 and the sum of their squares is 289. The sum of the number is:
 1) 20 2) 23 3) 169 4) 400 5) None of these
Explanation :
Let the numbers be x and y.
Then, xy = 120 and x2 + y= 289.
(x + y)2 = x2 + y+ 2xy = 289 + (2 x 120) = 529
x + y = 23.