The owner of a milk store finds that, he can sell 980 litres of milk each week at Rs 14/litre and 1220 litres of milk each week at Rs 16/litre. Assuming a linear relationship between selling price and demand, how many litres could he sell weekly at Rs 17/litre?


The relationship between selling price and demand is linear.


Assuming selling price per litre along X-axis and demand along Y-axis, we have two points (14, 980) and (16, 1220) in XY-plane.


We know that the equation of the line passing through the points (x1, y1) and (x2, y2) is given by




y 980 = 120 (x 14)


y = 120 (x 14) + 980


When x = Rs 17/litre,


y = 120 (17 14) + 980


y = 120(3) + 980


y = 360 + 980 = 1340


Ans. The owner can sell 1340 litres weekly at Rs 17/litre.


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