A trader paid Tk. 300 for a shipment of x identical pens. The trader gave two pens free of cost and sold each for Tk. 5 more than the average cost of the x pens. If the total revenue from the sale of the pens was Tk. 120 more than the cost of the shipment, how many pens were in the shipment?

If the average of 5 positive integers is 40 and the difference between the largest and the smallest of these 5 numbers is 10, what is the maximum value possible for the largest of these integers?

$a-\frac{1}{a}$=3 হলে $a^3-\frac{1}{a^3}$ এর মান কত?

A customer came to a shop and asked the shop manager to give a 20% discount on the listed price of a pen. Moreover, for every 10 pens purchased, he wanted two pens free of cost. The manager agreed to the customer's offer because he could still make a profit of 20% on the cost price of a pen. What was the listed price of the pen?