UPSC 2015 CDS I Math Paper

1990×2−173×23=1
Multiplying both sides by 11, we have
1990×22−173×253=11
So,x=22 and y=253 is a solution of the equation 1990x−173y=11Hence, statement (1) is incorrect
3x−12y=7
⇒x−4y=

7

3

Now, for any integral values of x and y, the LHS is an integer. But, RHS is not an integer
So, the equation 3x−12y=7 has no solution in integers for x and y.
Hence, statement (2) is correct.