PSLE The airmail rates to two countries are shown. Sarah sent a letter weighing 87g to Indonesia and a letter weighing 30g to China by airmail. How much did she pay altogether?
Mass |
Indonesia |
China |
First 40g |
$0.75 |
$1.60 |
Every additional 20g |
$0.45 |
$0.70 |
Mass of the letter to Indonesia excluding the first 40 g
= 87 - 40
= 47 g
Sets of additional 20 g of the letter to Indonesia
= 47 ÷ 20
= 2 r 7
Sets of additional 20 g and part thereof the letter to Indonesia
= 2 + 1
= 3
Amount that Sarah paid for the letter to Indonesia
= 0.75 + 3 x 0.45
= 0.75 + 1.35
= $2.10
Amount that Sarah paid altogether
= 2.10 + 1.60
= $3.70
Answer(s): $3.70