a) It has been observed that 4 out of every 100 manufactured bulbs are defective. A random sample of 12 a selected at random bulbs is selected from a day's batch. Determine the probability that among the selected bulbs, (i) less than 3 are defective. (3 marks (ii) at least two are defective. (3 marks​

The function a represents the cost of manufacturing product a, in hundreds of dollars, and the function b represents the cost of manufacturing product b, in hundreds of dollars. a(t) = 5t + 2 b(t) = 7t - 2t +4 find the expression that describes the total cost of manufacturing both products, a(t) + b(t). a. 7t^2 - 7t + 2 b. 7t^2 + 3 +6 c. 7t^2 + 7t - 6 d. 7t^2 - 3t + 6