PSLE The airmail rates to two countries are shown. Min sent a letter weighing 89g to Laos and a letter weighing 37g to Switzerland by airmail. How much did she pay altogether?
Mass |
Laos |
Switzerland |
First 40g |
$0.55 |
$1.90 |
Every additional 20g |
$0.15 |
$0.75 |
Mass of the letter to Laos excluding the first 40 g
= 89 - 40
= 49 g
Sets of additional 20 g of the letter to Laos
= 49 ÷ 20
= 2 r 9
Sets of additional 20 g and part thereof the letter to Laos
= 2 + 1
= 3
Amount that Min paid for the letter to Laos
= 0.55 + 3 x 0.15
= 0.55 + 0.45
= $1.00
Amount that Min paid altogether
= 1.00 + 1.90
= $2.90
Answer(s): $2.90