PSLE The airmail rates to two countries are shown. Wendy sent a letter weighing 87g to Laos and a letter weighing 22g to Canada by airmail. How much did she pay altogether?
Mass |
Laos |
Canada |
First 30g |
$0.75 |
$1.70 |
Every additional 15g |
$0.35 |
$0.65 |
Mass of the letter to Laos excluding the first 30 g
= 87 - 30
= 57 g
Sets of additional 15 g of the letter to Laos
= 57 ÷ 15
= 3 r 12
Sets of additional 15 g and part thereof the letter to Laos
= 3 + 1
= 4
Amount that Wendy paid for the letter to Laos
= 0.75 + 4 x 0.35
= 0.75 + 1.40
= $2.15
Amount that Wendy paid altogether
= 2.15 + 1.70
= $3.85
Answer(s): $3.85