PSLE The airmail rates to two countries are shown. Lucy sent a letter weighing 81g to Vietnam and a letter weighing 48g to Switzerland by airmail. How much did she pay altogether?
Mass |
Vietnam |
Switzerland |
First 50g |
$0.65 |
$1.90 |
Every additional 25g |
$0.45 |
$0.85 |
Mass of the letter to Vietnam excluding the first 50 g
= 81 - 50
= 31 g
Sets of additional 25 g of the letter to Vietnam
= 31 ÷ 25
= 1 r 6
Sets of additional 25 g and part thereof the letter to Vietnam
= 1 + 1
= 2
Amount that Lucy paid for the letter to Vietnam
= 0.65 + 2 x 0.45
= 0.65 + 0.90
= $1.55
Amount that Lucy paid altogether
= 1.55 + 1.90
= $3.45
Answer(s): $3.45