1.  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 ?
A. 600q - 5t
B. 500q - 4t
C. 600q - 4t
D. 500q - 5t

Answer: Option D

Explanation:

By Hit and Trial ,

Case I t = ₹ 400 and q = 20 unit

Then, from option (a),

Total profit = 600q - 5t

= 600 x 20 - 5 x 400

= 12000 - 2000 = ₹ 10000


Case II t ₹ 600 and q = 25 units

Total profit = 600q - 5t

⇒ 600 x 25 - 5 x 600

⇒ 600(25 - 5)

⇒ 600 x 20

∴ ₹ 12000