PSLE The airmail rates to two countries are shown. Opal sent a letter weighing 61g to Laos and a letter weighing 22g to India by airmail. How much did she pay altogether?
Mass |
Laos |
India |
First 30g |
$0.75 |
$1.50 |
Every additional 15g |
$0.55 |
$0.45 |
Mass of the letter to Laos excluding the first 30 g
= 61 - 30
= 31 g
Sets of additional 15 g of the letter to Laos
= 31 ÷ 15
= 2 r 1
Sets of additional 15 g and part thereof the letter to Laos
= 2 + 1
= 3
Amount that Opal paid for the letter to Laos
= 0.75 + 3 x 0.55
= 0.75 + 1.65
= $2.40
Amount that Opal paid altogether
= 2.40 + 1.50
= $3.90
Answer(s): $3.90