PSLE The airmail rates to two countries are shown. Xuan sent a letter weighing 91g to Laos and a letter weighing 36g to Sweden by airmail. How much did she pay altogether?
Mass |
Laos |
Sweden |
First 40g |
$0.85 |
$1.40 |
Every additional 20g |
$0.55 |
$0.50 |
Mass of the letter to Laos excluding the first 40 g
= 91 - 40
= 51 g
Sets of additional 20 g of the letter to Laos
= 51 ÷ 20
= 2 r 11
Sets of additional 20 g and part thereof the letter to Laos
= 2 + 1
= 3
Amount that Xuan paid for the letter to Laos
= 0.85 + 3 x 0.55
= 0.85 + 1.65
= $2.50
Amount that Xuan paid altogether
= 2.50 + 1.40
= $3.90
Answer(s): $3.90