PSLE The airmail rates to two countries are shown. Yen sent a letter weighing 78g to Thailand and a letter weighing 39g to India by airmail. How much did she pay altogether?
Mass |
Thailand |
India |
First 40g |
$0.55 |
$1.30 |
Every additional 20g |
$0.25 |
$0.45 |
Mass of the letter to Thailand excluding the first 40 g
= 78 - 40
= 38 g
Sets of additional 20 g of the letter to Thailand
= 38 ÷ 20
= 1 r 18
Sets of additional 20 g and part thereof the letter to Thailand
= 1 + 1
= 2
Amount that Yen paid for the letter to Thailand
= 0.55 + 2 x 0.25
= 0.55 + 0.50
= $1.05
Amount that Yen paid altogether
= 1.05 + 1.30
= $2.35
Answer(s): $2.35