PSLE The airmail rates to two countries are shown. Tiffany sent a letter weighing 74g to Vietnam and a letter weighing 10g to Australia by airmail. How much did she pay altogether?
Mass |
Vietnam |
Australia |
First 20g |
$0.55 |
$1.70 |
Every additional 10g |
$0.15 |
$0.55 |
Mass of the letter to Vietnam excluding the first 20 g
= 74 - 20
= 54 g
Sets of additional 10 g of the letter to Vietnam
= 54 ÷ 10
= 5 r 4
Sets of additional 10 g and part thereof the letter to Vietnam
= 5 + 1
= 6
Amount that Tiffany paid for the letter to Vietnam
= 0.55 + 6 x 0.15
= 0.55 + 0.90
= $1.45
Amount that Tiffany paid altogether
= 1.45 + 1.70
= $3.15
Answer(s): $3.15