Explanation:
It is given that in the market there are four equal-sized firms that produce similar products. The market is saturated such that 10% industry-wide price rise would lead to 18% decline in units sold by all firms in the industry. Going further, there is a proposed legislation that imposes a tariff on a key input used by the industry, which on realization would result in the increase in marginal cost by $2.
This means that the market elasticity of demand is:
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