Assuming that profit of a shopkeeper in a particular commodity is a linear expression of transportation charge (t) and the quantity of commodity (q) . He earns a profit of ₹ 10000 by selling 20 units at the transport charge of ₹ 400. He also earn a profit of ₹ 12000 by selling 25 units at the transport charge of ₹ 600. What is the linear expression in t and q?

• 600q - 5t
• 500q - 4t
• 600q - 4t
• 500q - 5t