Answer:
The cheapest way to purchase 9 liters of orange juice would be to buy 3 promotions of 2 1.5 liter bottles of drink at £ 5 each promotion, totaling £ 15.
Step-by-step explanation:
To obtain the cheapest way to buy 9 liters of orange juice, the cost per liter of each type of container must be determined:
500 ml bottle = £1.15 (£2.30 per liter)
1.5 l carton = £2.70 (£1.80 per liter)
2 cartons of 1.5 l = £5 (£1.66 per liter)
3.5 l carton = £5.75 (£1.64 per liter)
Thus, there is in principle a staggered way to buy the drink: 2 cartons of 3.5 liters, plus 1 carton of 1.5 liters, plus 1 bottle of 500 ml, which would add up to a total cost of £15.35 (5.75 x 2 + 2.70 + 1.15) .
Now, you could also take advantage of the promotion of 2 cartons of 1.5 l at £5, with which buying 3 of these promotions would acquire the 9 liters of drink (1.5 x 2 x 3) at £15 (3 x 5).
Thus, the cheapest way to purchase 9 liters of orange juice would be to buy 3 promotions of 2 1.5 liter bottles of drink at £ 5 each promotion, totaling £ 15.