PSLE The airmail rates to two countries are shown. Gwen sent a letter weighing 51g to Thailand and a letter weighing 14g to New Zealand by airmail. How much did she pay altogether?
Mass |
Thailand |
New Zealand |
First 20g |
$0.65 |
$1.10 |
Every additional 10g |
$0.45 |
$0.45 |
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 Gwen paid for the letter to Thailand
= 0.65 + 4 x 0.45
= 0.65 + 1.80
= $2.45
Amount that Gwen paid altogether
= 2.45 + 1.10
= $3.55
Answer(s): $3.55