The table shows the airmail rates for sending letters and postcards to some countries.
Destination |
Letters |
Postcards |
|
Mass |
Postage Rate |
Per piece |
Thailand, Vietnam, Myanmar
|
1st 30 g |
$1.30 |
$0.60
|
Every additional 10 g or part thereof |
$0.30 |
How much did Irene pay for the postage when she sent a letter which weighed 108 g and 9 postcards to Vietnam by airmail?
Remaining mass that Irene had to pay for the letter as it was more than 30 g
= 108 - 30
= 78 g
Number of sets of additional 10 g of the letter that Irene had to pay for
= 78 ÷ 10
= 7 r 8
Total number of sets of additional 10 g of the letter that Irene had to pay for
= 7 + 1
= 8
Amount that Irene had to pay for the sets of additional 10 g of the letter
= 8 x 0.30
= $2.40
Total amount that Irene had to pay for the letter
= 1.30 + 2.40
= $3.70
Amount that Irene had to pay for the 9 postcards
= 9 x 0.60
= $5.40
Total amount that Irene paid
= 3.70 + 5.40
= $9.10
Answer(s): $9.10