Let the cost of a bat be Rs. x and cost of a ball be Rs. y.Then algebraically representation of the question is -3x+6y=3900⇒x+2y=1300......(1)x+3y=1300........(2)To represent it geometrically, we plot the two equationsx+3y=1300⇒y=31300−x​ x100 0 1300  y=31300−x​ 40031300​ 0 x+2y=1300⇒y=21300−x​ x100 0 1300  y=21300−x​600650 0 As we can see, the lines intersect at (1300,0) which is the solution for this question.