Assume that the marginal cost to a grocery store of selling a bottle of salad dressing to customers who present coupons versus those who don't is identical and equal to $1.50. If the elasticity of demand of coupon holders is 5 versus 1.25 for other customers, how much of a per-unit discount should the store give coupon holders? What if the coupon holders have an elasticity of 2-how would the answer change?