Aptitude - Problems on H.C.F and L.C.M - Discussion
Discussion Forum : Problems on H.C.F and L.C.M - General Questions (Q.No. 5)
5.
The greatest number of four digits which is divisible by 15, 25, 40 and 75 is:
Answer: Option
Explanation:
Greatest number of 4-digits is 9999.
L.C.M. of 15, 25, 40 and 75 is 600.
On dividing 9999 by 600, the remainder is 399.
Required number (9999 - 399) = 9600.
Discussion:
120 comments Page 7 of 12.
Sruthi said:
1 decade ago
5) 15,25,40,75
------------
5) 3,5,8,15
------------
3) 3,1,8,3
------------
1,1,8,1
Now,
LCM = 5*5*3*8 = 600.
------------
5) 3,5,8,15
------------
3) 3,1,8,3
------------
1,1,8,1
Now,
LCM = 5*5*3*8 = 600.
Achutha said:
1 decade ago
Please tell why we have to take lcm instead instead of hcf and in which situation I have to take lcm or hcf?
Shubhangi said:
1 decade ago
Why do we take LCM of the given numbers, but not HCF?
Sanesh said:
1 decade ago
How you get 399?
Heena said:
1 decade ago
We can also take 9800 as a base then we have to divide 9800 by 600 which gives 200 remainder and we subtract 200 from 9800 will give the answer 9600.
Atul said:
1 decade ago
How to devide 9999 by 600? please explain.
Rohir said:
1 decade ago
How that remainder come 399 please tell me?
Veeramani said:
1 decade ago
9999 divide 600 which give only remainder for 133 but there they are said 399 how its?
Anil said:
1 decade ago
What if we take 6 digits?
Siddharth said:
1 decade ago
Hi all,
Another method to answer this question is just break all four (15, 25, 40, 75) in to prime numbers.
15 = 5*3.
25 = 5*5.
40 = 8 (2*2*2) *5.
75 = 5*3*5.
Now here we can see the common divisors are 5, 3 and 8.
So the number which is divisible by 5, 3 and 8 is the right answer which is option C 9600.
Another method to answer this question is just break all four (15, 25, 40, 75) in to prime numbers.
15 = 5*3.
25 = 5*5.
40 = 8 (2*2*2) *5.
75 = 5*3*5.
Now here we can see the common divisors are 5, 3 and 8.
So the number which is divisible by 5, 3 and 8 is the right answer which is option C 9600.
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