The prices before and after are provided, but the quantities are only noted as Q1 and Q2, and, based on the increase or decrease, 

you can assign numbers arbitrarily to find the elasticity, use the TR=P*Q formula (that is total revenue),.

 

Recently, the Independent, a daily newspaper printed in London, announced a price cut to 30 pence (P2) from 50 pence (P1). As a result, daily circulation increased from Q1 copies to Q2 copies. Using the demand elasticity and Total revenue, please state whether the price cut was a justified managerial decision or not? Total revenue= Price * quantity?