PSLE The airmail rates to two countries are shown. Wendy sent a letter weighing 77g to Vietnam and a letter weighing 31g to Egypt by airmail. How much did she pay altogether?
Mass |
Vietnam |
Egypt |
First 40g |
$0.75 |
$1.60 |
Every additional 20g |
$0.55 |
$0.60 |
Mass of the letter to Vietnam excluding the first 40 g
= 77 - 40
= 37 g
Sets of additional 20 g of the letter to Vietnam
= 37 ÷ 20
= 1 r 17
Sets of additional 20 g and part thereof the letter to Vietnam
= 1 + 1
= 2
Amount that Wendy paid for the letter to Vietnam
= 0.75 + 2 x 0.55
= 0.75 + 1.10
= $1.85
Amount that Wendy paid altogether
= 1.85 + 1.60
= $3.45
Answer(s): $3.45