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 20 g |
$1.70 |
$0.80
|
Every additional 10 g or part thereof |
$0.35 |
How much did Irene pay for the postage when she sent a letter which weighed 74 g and 7 postcards to Thailand by airmail?
Remaining mass that Irene had to pay for the letter as it was more than 20 g
= 74 - 20
= 54 g
Number of sets of additional 10 g of the letter that Irene had to pay for
= 54 ÷ 10
= 5 r 4
Total number of sets of additional 10 g of the letter that Irene had to pay for
= 5 + 1
= 6
Amount that Irene had to pay for the sets of additional 10 g of the letter
= 6 x 0.35
= $2.10
Total amount that Irene had to pay for the letter
= 1.70 + 2.10
= $3.80
Amount that Irene had to pay for the 7 postcards
= 7 x 0.80
= $5.60
Total amount that Irene paid
= 3.80 + 5.60
= $9.40
Answer(s): $9.40