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 20 g	$0.80	$0.50
	Every additional 10 g or part thereof	$0.25

How much did Kimberly pay for the postage when she sent a letter which weighed 105 g and 3 postcards to Malaysia by airmail?
Remaining mass that Kimberly had to pay for the letter as it was more than 20 g
= 105 - 20
= 85 g

Number of sets of additional 10 g of the letter that Kimberly had to pay for 
= 85 ÷ 10
= 8 r 5

Total number of sets of additional 10 g of the letter that Kimberly had to pay for 
= 8 + 1
= 9

Amount that Kimberly had to pay for the sets of additional 10 g of the letter
= 9 x 0.25
= $2.25

Total amount that Kimberly had to pay for the letter
= 0.80 + 2.25
= $3.05

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

Total amount that Kimberly paid
= 3.05 + 1.50
= $4.55

Answer(s): $4.55