Sorry guest, I have only just seen your post. I could easily have missed it.
If you were a member you could have sent me a private message with the address of this thread and that way i could not have missed it.
-----
GOOD EXAMINATION GUEST! You are right. :)
Let m and n be positive integers such that m = 24n + 51.
What is the largest possible value of the greatest common divisor of 2m and 3n?
m=3(8n+17)
Ltt's consider where n is a multiple of 17
let n = 17k where k is a positive integer.
n=17k
m=3(8*17k+17)
m=3(9*17k) error m=3*17(8k+1)
----
3n=3*17 * k
2m=3*17 * 2(8k+1)
If k is even then 2 is another factor.
Assume k is even and let k=2c
3n=3*17 *2 * c
2m=3*17*2 (16c+1)
I do not think that c and 16c+1 can have any common factors.
Which means that the highest possible common factor is 3*17*2 = 102
So if n is a multiple of 34 the highest common factor is 102.
If n is a multiple of 17 but NOT of 2 then the highest common factor is 51
if n is not a multiple of 17 and is odd the HCF is 3
if n is not a multiple of 17even the HCF is 6
I think this is right.....