p,q and r are natural numbers such that p:q:r=2:3:6 sum of their squares is 3a6bc where a,b,c are unknown digits now consider following 1)number of factors of 3a6bc is 9 2)the three digit number 6bc divides the five digit number 3a6bc is 1&2 are true or false or 1 true
rileybiers:
so?
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p, q, r are positive integer numbers. a, b, c are single digit integers from 0 to 9.
p : q : r = 2 : 3 : 6 Let the constant of proportionality be x (rational number).
p = 2x q = 3x r = 6x
p² + q² + r² = 3a6bc
4x²+9x²+36x² = 30,000+a*1,000+600+b*10+c
49 x² = 30,600+1000*a+10*b+c or 3a6bc
Then factors of LHS are :
1, 7, 49, x, 7x, 49x, x², 7 x², 49x²
there are 9 factors.
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6bc divides 3a6bc ??
3a6bc is in the range: 39,699 --- 30,600
3a6bc = 3a * 1000 + 6bc
3a6bc / 6bc = 3a*1000/6bc + 1
49 * 25 * 25 = 30625 that is : a = 0, b = 2 and c = 5.
so 6bc divides 3a6bc for the above numbers.
perhaps more numbers too..
================
The solution:
the range of 3a6bc is 39699 to 30600.
so range of x² is from 39699/49 = 810.1 to 624.48
so range of x is from: 28 to 25.
so 49 * 625 = 30625 =======> this is right.
49 * 26² = 33124
49 * 27² = 35721
======================
Deductive way of solving this problem.
N = 49 * x² = 3a6bc
if 6bc is a factor of 3a6bc, then 6bc is a multiple of 7, 7², x².
625 = 25² is a perfect square. trying it works.
p : q : r = 2 : 3 : 6 Let the constant of proportionality be x (rational number).
p = 2x q = 3x r = 6x
p² + q² + r² = 3a6bc
4x²+9x²+36x² = 30,000+a*1,000+600+b*10+c
49 x² = 30,600+1000*a+10*b+c or 3a6bc
Then factors of LHS are :
1, 7, 49, x, 7x, 49x, x², 7 x², 49x²
there are 9 factors.
========================
6bc divides 3a6bc ??
3a6bc is in the range: 39,699 --- 30,600
3a6bc = 3a * 1000 + 6bc
3a6bc / 6bc = 3a*1000/6bc + 1
49 * 25 * 25 = 30625 that is : a = 0, b = 2 and c = 5.
so 6bc divides 3a6bc for the above numbers.
perhaps more numbers too..
================
The solution:
the range of 3a6bc is 39699 to 30600.
so range of x² is from 39699/49 = 810.1 to 624.48
so range of x is from: 28 to 25.
so 49 * 625 = 30625 =======> this is right.
49 * 26² = 33124
49 * 27² = 35721
======================
Deductive way of solving this problem.
N = 49 * x² = 3a6bc
if 6bc is a factor of 3a6bc, then 6bc is a multiple of 7, 7², x².
625 = 25² is a perfect square. trying it works.
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