Monday, September 10, 2012

Excercise On LCM and HCF


1.    Four different electronic devices make a beep after every 30 minutes,   1 hour, 1 and half  hour      and 1 hour 45 minutes respectively.      All the devices beeped together at 12 noon. They will again beep together at:
[A] 12 midnight    [B] 6 a.m. [C] 3 a.m. [D] 9 a.m.
2.    The H.C.F of 204, 1190 and 1445 is:
[A] 17     [B] 19     [C] 18     [D] 21
3.    The least multiple of 7, which leaves a remainder of 4. when divided by 6, 9, 15 and 18 is:
[A] 74     [B] 184     [C] 94     [D] 364
4.  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:
[A] 1677    [B] 2523    [C] 1683    [D] 3363
5.  Find the greatest number that    will divide 43, 91 and 183 so as to leave the same remainder in each case. 
[A] 4 [B] 9 [C] 7 [D] 13
6.  The smallest number which when diminished by 7, is divisible by 12, 16, 18, 21 and 28 is:
[A] 1008    [B] 1022    [C] 1015    [D] 1032
7.  The maximum number of students among them 1001 pens and 910 pencils can be distributed in such a way that each student gets the same number of pens and same number of pencils is:
[A] 91     [B] 1001    [C] 910    [D] 191116.
8.  The least number, which when divided by 12, 15, 20 and 54 leaves in each case a remainder of 8, is:
[A] 504     [B] 544     [C] 536    [D] 548
9.  Find the least number    which when divided by 16, 18, 20 and 25 leaves 4 as remainder in each case, but when divided by 7 leaves no remainder. 
[A] 17004   [B] 18002  [C] 18000  [D] 18004
10.  Find the least multiple of 23, which when divided by   18, 21 and 24 leaves remainders 7, 10 and 13 respectively. 
[A] 3002    [B] 3024   [C] 3013    [D] 3036
11.  The largest four – digit number which     when divided by 4, 7 or 13 leaves a remainder of 3 in each case, is 
[A] 8739 [B] 9834 [C] 9831 [D] 9893
12.  The L.C.M. of 22, 54, 108, 135 and 198 is:
[A] 330 [B] 5940 [C] 1980 [D] 11880
13.  Six bells commence     tolling together and toll at intervals of 2, 4, 6, 8, 10 and 12 seconds respectively. In 30 minutes, how many times do they toll together? 
[A] 4 [B] 15 [C] 10[D] 16
14. The H.C.F of 2923 and 3239 is :
[A] 37 [B] 73 [C] 47 [D] 79
15.  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:
[A] 279 [B] 308 [C] 283 [D] 318
16.  The least number which should be added to 2497 so that the sum is exactly divisible by 5, 6, 4 and 3 is:
[A] 3 [B] 23 [C] 13 [D] 33
17.  The    product of the L.C.M. and   H.C.F. of two numbers is 24. The difference of two numbers is 2. Find the numbers. 
[A] 2 and 4 [B] 8 and 6 [C] 6 and 4 [D] 8 and 10
18.  The least number which when increased by 5 is divisible by each one of 24, 32, 36 and 54, is
[A] 427 [B] 869 [C] 859 [D] 4320
19.  The ratio of two numbers is 3 : 4 and their H.C.F. is 4. Their L.C.M. is:
[A] 12 [B] 24 [C] 16 [D] 48
20.  The greatest number of four digits which is divisible by 15, 25, 40 and 75 is:
[A] 9000    [B] 9600   [C] 9400    [D] 9800
21.  The product of two   numbers is 1320 and their H.C.F. is 6. the L.C.M. of the numbers is: 
[A] 220 [B] 1326 [C] 1314 [D] 7920
22.  The least number of five digits which is exactly divisible by 12, 15 and 18, is:
[A] 10010 [B] 10020 [C] 10015 [D] 10080
23.  The H.C.F. and L.C.M. of two numbers are 11 and 385 respectively. If one number lies between 75 and 125, then that number is:
[A] 77 [B] 99 [C] 88 [D] 110
24.  The greatest   number which can divide 1356, 1868 and 2764 leaving the same remainder 12 in each case, is: 
[A] 64     [B] 156     [C] 124   [D] 260

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