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

Destination	Letters		Postcards
	Mass	Postage Rate	Per piece
New Zealand, Australia	1st 30 g	$1.50	$0.70
	Every additional 10 g or part thereof	$0.35

How much did Olivia pay for the postage when she sent a letter which weighed 86 g and 7 postcards to New Zealand by airmail?
Remaining mass that Olivia had to pay for the letter as it was more than 30 g
= 86 - 30
= 56 g

Number of sets of additional 10 g of the letter that Olivia had to pay for 
= 56 ÷ 10
= 5 r 6

Total number of sets of additional 10 g of the letter that Olivia had to pay for 
= 5 + 1
= 6

Amount that Olivia had to pay for the sets of additional 10 g of the letter
= 6 x 0.35
= $2.10

Total amount that Olivia had to pay for the letter
= 1.50 + 2.10
= $3.60

Amount that Olivia had to pay for the 7 postcards
= 7 x 0.70
= $4.90

Total amount that Olivia paid
= 3.60 + 4.90
= $8.50

Answer(s): $8.50