Answer:
(a) The boxes with the weights 6.4 kg, 7.2 kg, and 6.3 kg are the three of the boxes which have a total weight nearest to 20 kg but still less than 20 kg.
(b) Total cost of sending all four boxes together = £10.15
Explanation:
Note: This question is not complete. The complete question is therefore provided before answering the question as follows:
A postal carrier charges £8.95 up to 20 kg then 20p for each kg over that weight. Jane wants to send four boxes to the same address. The boxes weigh 6.4 kg, 7.2 kg, 6.3 kg, 6.1 kg.
(a) Which three of the boxes have a total weight nearest to 20 kg but still less than 20 kg?
(b) Work out the total cost of sending all four boxes together.
The explanation of the answer is now given as follows:
(a) Which three of the boxes have a total weight nearest to 20 kg but still less than 20 kg?
The boxes with the weights 6.4 kg, 7.2 kg, and 6.3 kg are the three of the boxes which have a total weight nearest to 20 kg but still less than 20 kg.
This is because, the addition of the weights of the three boxes is the highest and it is 19.90 kg as follows:
6.4 + 7.2 kg + 6.3 kg = 19.90 kg
(b) Work out the total cost of sending all four boxes together.
The total kg can be calculated as follows:
6.4 + 7.2 kg + 6.3 kg + 6.1 kg = 26 kg
Additional kg = 26 kg - 20 kg = 6kg
Cost of 20 kg = £8.95
Cost of 6 kg = 6 kg * 20p = 120p = 120p / 100 = £1.20
Total cost of sending all four boxes together = Cost of 20 kg + Cost of 6 kg = £8.95 + £1.20 = £10.15