PSLE The airmail rates to two countries are shown. Betty sent a letter weighing 54g to Vietnam and a letter weighing 13g to Sweden by airmail. How much did she pay altogether?
Mass |
Vietnam |
Sweden |
First 20g |
$0.65 |
$1.40 |
Every additional 10g |
$0.35 |
$0.50 |
Mass of the letter to Vietnam excluding the first 20 g
= 54 - 20
= 34 g
Sets of additional 10 g of the letter to Vietnam
= 34 ÷ 10
= 3 r 4
Sets of additional 10 g and part thereof the letter to Vietnam
= 3 + 1
= 4
Amount that Betty paid for the letter to Vietnam
= 0.65 + 4 x 0.35
= 0.65 + 1.40
= $2.05
Amount that Betty paid altogether
= 2.05 + 1.40
= $3.45
Answer(s): $3.45