 Hello and welcome to this session, let us understand the following question which says, the total cost Cx in rupees associated with the production of x units of an item is given by Cx is equal to 0.007 x cube minus 0.003 x square plus 15x plus 4000. Find the marginal cost when 17 units are produced. Now let us proceed on to the solution. Given to us Cx is equal to 0.07 x cube minus 0.003 x square plus 15x plus 4000. Now differentiating it with respect to x we get d by dx of C of x is equal to 0.007 multiplied by 3x square minus 0.003 multiplied by 2x plus 15 plus 0. It is given to us that marginal cost is equal to 17 units. Therefore when x is equal to 17 that is the marginal cost d by dx of C of x is equal to 0.007 multiplied by 3 multiplied by 17 square minus 0.003 multiplied by 2 multiplied by 17 plus 15. It is equal to 0.007 multiplied by 3 17 square is 289 minus 0.003 multiplied by 17 to the 34 plus 15. It is equal to 0.007 multiplied by 289 multiplied by 3 is equal to 867 minus 0.003 multiplied by 34 plus 15. It is equal to 0.007 multiplied by 867 is equal to 6069 minus 0.003 multiplied by 34 is 0.102 plus 15. It is equal to 6.069 plus 15 is equal to 21.069 minus 0.102 which is equal to 20.967. Hence required marginal cost is equal to rupees 20.967 which is the required answer. I hope you understood this question. That's all for the session. Bye and have a nice day.