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### BdMO 2017 Dhaka divitional

Posted: **Wed Mar 28, 2018 8:02 pm**

by **soyeb pervez jim**

Two points $A(x_A, y_B), B(x_A+5,y_B+12 )$ are on parabola $5x^2-px-5y+q=0$ such that $x_A+y_B=5$. How many possible positive integer pairs $(p, q)$ are there where positive integer $q \leq 2050$ ?

### Re: BdMO 2017 Dhaka divitional

Posted: **Sun Feb 10, 2019 4:00 pm**

by **samiul_samin**

soyeb pervez jim wrote: ↑Wed Mar 28, 2018 8:02 pm

Two points $A(x_A, y_B), B(x_A+5,y_B+12 )$ are on parabola $5x^2-px-5y+q=0$ such that $x_A+y_B=5$. How many possible positive integer pairs $(p, q)$ are there where positive integer $q \leq 2050$ ?

**Use Modular Arithmatic**
**Answer**

### Re: BdMO 2017 Dhaka divitional

Posted: **Wed Feb 20, 2019 2:12 pm**

by **soyeb pervez jim**

May be the answer is $21+20=41$

$21$ for $q=5n^{2}-2n+22$ ; $20$ for $q=5n^{2}+2n+22$

### Re: BdMO 2017 Dhaka divitional

Posted: **Wed Feb 20, 2019 3:35 pm**

by **samiul_samin**

soyeb pervez jim wrote: ↑Wed Feb 20, 2019 2:12 pm

May be the answer is $21+20=41$

$21$ for $q=5n^{2}-2n+22$ ; $20$ for $q=5n^{2}+2n+22$

Then my solution is wrong.My solution is too long to post