PSLE The airmail rates to two countries are shown. Betty sent a letter weighing 72g to Laos and a letter weighing 34g to China by airmail. How much did she pay altogether?
Mass |
Laos |
China |
First 40g |
$0.85 |
$1.20 |
Every additional 20g |
$0.55 |
$0.40 |
Mass of the letter to Laos excluding the first 40 g
= 72 - 40
= 32 g
Sets of additional 20 g of the letter to Laos
= 32 ÷ 20
= 1 r 12
Sets of additional 20 g and part thereof the letter to Laos
= 1 + 1
= 2
Amount that Betty paid for the letter to Laos
= 0.85 + 2 x 0.55
= 0.85 + 1.10
= $1.95
Amount that Betty paid altogether
= 1.95 + 1.20
= $3.15
Answer(s): $3.15