Stuck on word problem
1.A company in manufacturing a new digital watch can sell all it manufactures. The cost (in dollars) is given by C(x)=5000+2x, where the production output in one day is x watches. If production is increasing at 5 watches per day when production is 375 watches per day, find the rate of increase in cost.
2. A beverage company works out a demand function for its sale of soda and finds it to be x=D(p)=4200-28p
where x=the quantity of sodas sold when the price per can, in cents, is p. At what prices, p, is the elasticity of demand inelastic?