The fuel consumption of a new model of car manufactured by Kantanka Automobile Limited is being tested.In one trial, 50 cars chosen at random were driven under identical conditions and the distance ,xkm on 1liter of petrol were recorded . The results gave the following totals. summation of x =525 , summation of x2=5625. Calculate the 95% confidence interval for the average petrol consumption, in kilometer per liter, of car of this type

Graph the function. Specify the intervals over which the function is increasing and the intervals where it is decreasing.y = 

A. Increasing -? < x ? 0

B. Decreasing 0 ? x < ?

C. Decreasing -? < x ? 0

D. Decreasing -? < x ? 0
Increasing 0 ? x < ?

Solve the problem.Suppose that the dollar cost of producing x radios is  Find the marginal cost when 40 radios are produced.

A. $14 B. $1480 C. -$1480 D. $46

Perform the indicated operations.(10x2 - xy - y2) + (x2 + 9xy + 5y2)

A. 11x2 + 8xy + 4y2 B. 11x2 + 10xy + 6y2 C. 9x2 - 10xy - 6y2 D. 10x2 + 9xy + 5y2

Solve the inequality, then graph the solution.7t + 5 ? 5t + 1

A. (-?, -2]

B. [2, ?)

C. (-?, 2]

D. [-2, ?)