11. [I6.66 Points] DETAILS WAN EFMAC7 13.4.057. MY NOTES PRACTICE ANOTHER 2 1,000 The marginal cost of producing the xth box of light bulbs is 4 + dollars per box. Determine how much is added to the total cost by a change in production from x = 30 to x = 90 boxes. $ Need Help? 12. [-I6.66 Points] DETAILS WANEFMAC7 13.4.062. MY NOTES PRACTICE ANOTHER A ball thrown in the air has a velocity of v(t) = 85 32t ft/sec at time t seconds. Find the total displacement of the ball between times t = 1 second and t = 6 seconds. ft Interpret your answer. The ball is feet lower after 6 seconds than it was at the end of the first second. Need Help