I think its -40 because it looks like you have negative 40 then ur adding 10
You made 3/20 of the 400 cards, which is 60 cards.
By first principles, the derivative is

Use the binomial theorem to expand the numerator:


where

The first term is eliminated, and the limit is

A power of
in every term of the numerator cancels with
in the denominator:

Finally, each term containing
approaches 0 as
, and the derivative is

Answer: 6247.5
Step-by-step explanation:
85% x 105000 = 89250
70 x 89.25 = 6247.5