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 |
$0.80 |
$0.90
|
Every additional 10 g or part thereof |
$0.45 |
How much did Irene pay for the postage when she sent a letter which weighed 75 g and 6 postcards to Thailand by airmail?
Remaining mass that Irene had to pay for the letter as it was more than 30 g
= 75 - 30
= 45 g
Number of sets of additional 10 g of the letter that Irene had to pay for
= 45 ÷ 10
= 4 r 5
Total number of sets of additional 10 g of the letter that Irene had to pay for
= 4 + 1
= 5
Amount that Irene had to pay for the sets of additional 10 g of the letter
= 5 x 0.45
= $2.25
Total amount that Irene had to pay for the letter
= 0.80 + 2.25
= $3.05
Amount that Irene had to pay for the 6 postcards
= 6 x 0.90
= $5.40
Total amount that Irene paid
= 3.05 + 5.40
= $8.45
Answer(s): $8.45