# The total cost C(x) in rupees associated with the production of x units of an item is given by $C(x) = 0.007 x^3 - 0.003 x^2 + 15x + 4000$. Find the marginal cost when 10 units are produced.

$(A)\; Rs 1.704$
$(B)\; Rs 17.04$
$(C)\; Rs 170.4$
$(D)\; Rs 1704$

Marginal cost $=\frac{dc}{dx} = 3 \times 0.007 x^2 - 2 \times 0.003 x+ 15$
$\; \; \; \; = 0.021 x^2 - 0.006 x + 15$
Marginal cost when $x = 10$ is$(0.021 \times 100 - 0.006 \times 10 + 15)$
$\; \; \; \; = Rs 17.04$