PSLE The airmail rates to two countries are shown. Kathy sent a letter weighing 73g to Laos and a letter weighing 17g to China by airmail. How much did she pay altogether?
Mass |
Laos |
China |
First 20g |
$0.65 |
$1.30 |
Every additional 10g |
$0.35 |
$0.45 |
Mass of the letter to Laos excluding the first 20 g
= 73 - 20
= 53 g
Sets of additional 10 g of the letter to Laos
= 53 ÷ 10
= 5 r 3
Sets of additional 10 g and part thereof the letter to Laos
= 5 + 1
= 6
Amount that Kathy paid for the letter to Laos
= 0.65 + 6 x 0.35
= 0.65 + 2.10
= $2.75
Amount that Kathy paid altogether
= 2.75 + 1.30
= $4.05
Answer(s): $4.05