JEE Advance - Mathematics (1998 - No. 20)
If $$\left( {P\left( {1,2} \right),\,Q\left( {4,6} \right),\,R\left( {5,7} \right)} \right)$$ and $$S\left( {a,b} \right)$$ are the vertices of a parrallelogram $$PQRS,$$ then
$$a = 2,\,b = 4$$
$$a = 3,\,b = 4$$
$$a = 2,\,b = 3$$
$$a = 3,\,b = 5$$