PSLE The airmail rates to two countries are shown. Dana sent a letter weighing 87g to Vietnam and a letter weighing 37g to Switzerland by airmail. How much did she pay altogether?
Mass |
Vietnam |
Switzerland |
First 40g |
$0.85 |
$1.20 |
Every additional 20g |
$0.55 |
$0.40 |
Mass of the letter to Vietnam excluding the first 40 g
= 87 - 40
= 47 g
Sets of additional 20 g of the letter to Vietnam
= 47 ÷ 20
= 2 r 7
Sets of additional 20 g and part thereof the letter to Vietnam
= 2 + 1
= 3
Amount that Dana paid for the letter to Vietnam
= 0.85 + 3 x 0.55
= 0.85 + 1.65
= $2.50
Amount that Dana paid altogether
= 2.50 + 1.20
= $3.70
Answer(s): $3.70