The table shows the airmail rates for sending letters and postcards to some countries.

Destination	Letters		Postcards
	Mass	Postage Rate	Per piece
Indonesia, Malaysia	1st 30 g	$1.20	$0.50
	Every additional 10 g or part thereof	$0.45

How much did Jade pay for the postage when she sent a letter which weighed 57 g and 3 postcards to Malaysia by airmail?
Remaining mass that Jade had to pay for the letter as it was more than 30 g
= 57 - 30
= 27 g

Number of sets of additional 10 g of the letter that Jade had to pay for 
= 27 ÷ 10
= 2 r 7

Total number of sets of additional 10 g of the letter that Jade had to pay for 
= 2 + 1
= 3

Amount that Jade had to pay for the sets of additional 10 g of the letter
= 3 x 0.45
= $1.35

Total amount that Jade had to pay for the letter
= 1.20 + 1.35
= $2.55

Amount that Jade had to pay for the 3 postcards
= 3 x 0.50
= $1.50

Total amount that Jade paid
= 2.55 + 1.50
= $4.05

Answer(s): $4.05