PSLE The airmail rates to two countries are shown. Olivia sent a letter weighing 70g to Vietnam and a letter weighing 36g to Canada by airmail. How much did she pay altogether?
Mass |
Vietnam |
Canada |
First 40g |
$0.55 |
$1.60 |
Every additional 20g |
$0.25 |
$0.60 |
Mass of the letter to Vietnam excluding the first 40 g
= 70 - 40
= 30 g
Sets of additional 20 g of the letter to Vietnam
= 30 ÷ 20
= 1 r 10
Sets of additional 20 g and part thereof the letter to Vietnam
= 1 + 1
= 2
Amount that Olivia paid for the letter to Vietnam
= 0.55 + 2 x 0.25
= 0.55 + 0.50
= $1.05
Amount that Olivia paid altogether
= 1.05 + 1.60
= $2.65
Answer(s): $2.65