The table shows the airmail rates for sending letters and postcards to some countries.
Destination |
Letters |
Postcards |
|
Mass |
Postage Rate |
Per piece |
New Zealand, Australia
|
1st 20 g |
$1.50 |
$0.60
|
Every additional 10 g or part thereof |
$0.30 |
How much did Esther pay for the postage when she sent a letter which weighed 78 g and 4 postcards to New Zealand by airmail?
Remaining mass that Esther had to pay for the letter as it was more than 20 g
= 78 - 20
= 58 g
Number of sets of additional 10 g of the letter that Esther had to pay for
= 58 ÷ 10
= 5 r 8
Total number of sets of additional 10 g of the letter that Esther had to pay for
= 5 + 1
= 6
Amount that Esther had to pay for the sets of additional 10 g of the letter
= 6 x 0.30
= $1.80
Total amount that Esther had to pay for the letter
= 1.50 + 1.80
= $3.30
Amount that Esther had to pay for the 4 postcards
= 4 x 0.60
= $2.40
Total amount that Esther paid
= 3.30 + 2.40
= $5.70
Answer(s): $5.70