Please help. How are these numbers calculated?

Assume the private marginal benefit from a good can be represented by the inverse demand equation, P= 100 - Q. Assume the private marginal cost of producing the good can be represented by the supply equation, P= 3Q. If consuming the good generates a negative externality of $10 for each unit consumed, calculate: a. The privately optimal level of consumption and production. b. The socially optimal level of consumption and production. c. The deadweight loss to society if no action is taken. a. The privately optimal level of consumption and production is 25.0 units. (Round your response to one decimal place.) b. The socially optimal level of consumption and production is 22.5 units. (Round your response to one decimal place.) c. The deadweight loss to society if no action is taken is $ 12.5 . (Round your response to one decimal place.)