PSLE The airmail rates to two countries are shown. Tiffany sent a letter weighing 77g to Thailand and a letter weighing 31g to India by airmail. How much did she pay altogether?
Mass |
Thailand |
India |
First 40g |
$0.85 |
$1.80 |
Every additional 20g |
$0.65 |
$0.60 |
Mass of the letter to Thailand excluding the first 40 g
= 77 - 40
= 37 g
Sets of additional 20 g of the letter to Thailand
= 37 ÷ 20
= 1 r 17
Sets of additional 20 g and part thereof the letter to Thailand
= 1 + 1
= 2
Amount that Tiffany paid for the letter to Thailand
= 0.85 + 2 x 0.65
= 0.85 + 1.30
= $2.15
Amount that Tiffany paid altogether
= 2.15 + 1.80
= $3.95
Answer(s): $3.95