PSLE The airmail rates to two countries are shown. Lucy sent a letter weighing 51g to Thailand and a letter weighing 15g to Egypt by airmail. How much did she pay altogether?
Mass |
Thailand |
Egypt |
First 20g |
$0.55 |
$1.10 |
Every additional 10g |
$0.15 |
$0.25 |
Mass of the letter to Thailand excluding the first 20 g
= 51 - 20
= 31 g
Sets of additional 10 g of the letter to Thailand
= 31 ÷ 10
= 3 r 1
Sets of additional 10 g and part thereof the letter to Thailand
= 3 + 1
= 4
Amount that Lucy paid for the letter to Thailand
= 0.55 + 4 x 0.15
= 0.55 + 0.60
= $1.15
Amount that Lucy paid altogether
= 1.15 + 1.10
= $2.25
Answer(s): $2.25