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. 7)
7.
Three number are in the ratio of 3 : 4 : 5 and their L.C.M. is 2400. Their H.C.F. is:
Answer: Option
Explanation:
Let the numbers be 3x, 4x and 5x.
Then, their L.C.M. = 60x.
So, 60x = 2400 or x = 40.
The numbers are (3 x 40), (4 x 40) and (5 x 40).
Hence, required H.C.F. = 40.
Discussion:
41 comments Page 2 of 5.
Sundar said:
10 years ago
3x*4x*5x=2400x.
1x gets cancelled.
Then 60x^2=2400;
x^2=40.
Then x is 2 root 10; Answer is wrong.
1x gets cancelled.
Then 60x^2=2400;
x^2=40.
Then x is 2 root 10; Answer is wrong.
(1)
Master said:
9 years ago
LCM = 2400.
2400/60 = 40 => Right answer.
2400/60 = 40 => Right answer.
Pappu said:
10 years ago
Simply explain what is L.C.M and H.C.F please?
Aadi said:
9 years ago
I didn't understand one thing.
Why you guys convert ratio to multiplication?
For eg: 3 : 4 : 5 to 3 * 4 * 5 = 60.
2400/60 = 40?
Why you guys convert ratio to multiplication?
For eg: 3 : 4 : 5 to 3 * 4 * 5 = 60.
2400/60 = 40?
Kishore said:
9 years ago
I did like this but fails.
3x * 4x * 5x = 2400 * (h.c.f = x)
Square of x = 40
Can anyone help me?
3x * 4x * 5x = 2400 * (h.c.f = x)
Square of x = 40
Can anyone help me?
Arunkumar s said:
9 years ago
Do the equation product of numbers = HCF * LCM only used in two numbers?
Arnab said:
8 years ago
Yes @Arunkmar S.
@Kishore.
Here the proportion(3:4:5) can be written like this 3x, 4x, & 5x.
So LCM (3x,4x,5x)= x*3*4*5 = 60x.
But the LCM is 2400(given) so, your x=2400/60 = 40.
The required numbers are 3*40=120, 4*40=160, 5 * 40= 200.
Now find the HCF of 120, 160, 200 i.e. 40.
Simple right?
@Kishore.
Here the proportion(3:4:5) can be written like this 3x, 4x, & 5x.
So LCM (3x,4x,5x)= x*3*4*5 = 60x.
But the LCM is 2400(given) so, your x=2400/60 = 40.
The required numbers are 3*40=120, 4*40=160, 5 * 40= 200.
Now find the HCF of 120, 160, 200 i.e. 40.
Simple right?
Shekinarose said:
8 years ago
Can anyone explain where 60 came from?
Ramya said:
8 years ago
What is the relationship between the product of three numbers and their L.C.M and H.C.F. Please, anyone explain me?
Akash kandwal said:
7 years ago
Actually, the numbers given are in a ratio so we have to take in : 1/60.
So lcm:=1/2400,
and then,
The product of number=lcm of number*hcf of number;
1/60=1/2400*HCF.
HCF=40.
So lcm:=1/2400,
and then,
The product of number=lcm of number*hcf of number;
1/60=1/2400*HCF.
HCF=40.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers