PSLE The airmail rates to two countries are shown. Rachel sent a letter weighing 71g to Laos and a letter weighing 32g to New Zealand by airmail. How much did she pay altogether?
Mass |
Laos |
New Zealand |
First 40g |
$0.85 |
$1.70 |
Every additional 20g |
$0.45 |
$0.55 |
Mass of the letter to Laos excluding the first 40 g
= 71 - 40
= 31 g
Sets of additional 20 g of the letter to Laos
= 31 ÷ 20
= 1 r 11
Sets of additional 20 g and part thereof the letter to Laos
= 1 + 1
= 2
Amount that Rachel paid for the letter to Laos
= 0.85 + 2 x 0.45
= 0.85 + 0.90
= $1.75
Amount that Rachel paid altogether
= 1.75 + 1.70
= $3.45
Answer(s): $3.45