I'm struggling to calculate these practice questions could you help?

Suppose the marginal costs of emissions abatement for two polluting firms are as follows:

Producer 1:MC1= 10Q1

Producer 2:MC2= 50Q2

WhereMC1andMC2are the marginal control costs andQ1andQ2are the volumes of emissions reduced by Producers 1 and 2 respectively. With no controls at all, each firm emits 100 units totaling 200 units.

1. Compute the cost-effective allocation of control responsibility if a total reduction of 50 emission units is required (i.e. Q1 + Q2 = 50).
2. If the Government wants to charge an emission tax, what per unit tax should they impose?
3. How much total revenue would the Government collect from the tax on emissions in section b?
4. What other policy instrument can achieve a cost-effective reduction in emissions? Explain.