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	$1.20	$0.80
	Every additional 10 g or part thereof	$0.45

How much did Hazel pay for the postage when she sent a letter which weighed 73 g and 3 postcards to Thailand by airmail?
Remaining mass that Hazel had to pay for the letter as it was more than 30 g
= 73 - 30
= 43 g

Number of sets of additional 10 g of the letter that Hazel had to pay for 
= 43 ÷ 10
= 4 r 3

Total number of sets of additional 10 g of the letter that Hazel had to pay for 
= 4 + 1
= 5

Amount that Hazel had to pay for the sets of additional 10 g of the letter
= 5 x 0.45
= $2.25

Total amount that Hazel had to pay for the letter
= 1.20 + 2.25
= $3.45

Amount that Hazel had to pay for the 3 postcards
= 3 x 0.80
= $2.40

Total amount that Hazel paid
= 3.45 + 2.40
= $5.85

Answer(s): $5.85