Answer:
A) the demand is elastic since the PED = 6
B) total revenue will increase from $300 to $600
Explanation:
we can calculate the price elasticity of demand using the formula:
PED = % change in quantity demanded / % change in price = [(300 - 100) / 100] / [(1 - 1.5) / 1.5] = (200 / 100) / (-0.5 / 1.5) = 2 / 0.33 = 6
if the PED is the same when the price decreases from $1 to $0.50, total revenue will   :
when price = $1, total revenue = $1 x 300 = $300
when price = $0.50, total revenue = $0.50 x 1,200 = $600
*a 50% decrease in the price will cause a 300% increase (= 50% x 6) increase in the quantity demanded = 300 units + (300 x 300%) = 1,200 units