PSLE The airmail rates to two countries are shown. Xuan sent a letter weighing 69g to Thailand and a letter weighing 19g to New Zealand by airmail. How much did she pay altogether?
Mass |
Thailand |
New Zealand |
First 20g |
$0.85 |
$1.70 |
Every additional 10g |
$0.65 |
$0.65 |
Mass of the letter to Thailand excluding the first 20 g
= 69 - 20
= 49 g
Sets of additional 10 g of the letter to Thailand
= 49 ÷ 10
= 4 r 9
Sets of additional 10 g and part thereof the letter to Thailand
= 4 + 1
= 5
Amount that Xuan paid for the letter to Thailand
= 0.85 + 5 x 0.65
= 0.85 + 3.25
= $4.10
Amount that Xuan paid altogether
= 4.10 + 1.70
= $5.80
Answer(s): $5.80