We have to calculate the total cost of the meal. We know that Adam ( A ) and his dad ( D ) share the cost of the meal in the ratio 2 : 3 and that Adam`s dad pays 52.20 Pounds. So A : D = 2 : 3; A : 52.20 = 2 : 3. Using the cross products, A * 3 = 2 * 52.20; A * 3 = 104.40; A = 104.40 : 3; A = 34.80 Pounds. Finally, A + D = 34.80 + 52.20 = 87.00. Answer: The total cost of the meal is 87 Pounds.