PSLE The airmail rates to two countries are shown. Usha sent a letter weighing 51g to Vietnam and a letter weighing 13g to Egypt by airmail. How much did she pay altogether?
Mass |
Vietnam |
Egypt |
First 20g |
$0.65 |
$1.30 |
Every additional 10g |
$0.25 |
$0.35 |
Mass of the letter to Vietnam excluding the first 20 g
= 51 - 20
= 31 g
Sets of additional 10 g of the letter to Vietnam
= 31 ÷ 10
= 3 r 1
Sets of additional 10 g and part thereof the letter to Vietnam
= 3 + 1
= 4
Amount that Usha paid for the letter to Vietnam
= 0.65 + 4 x 0.25
= 0.65 + 1.00
= $1.65
Amount that Usha paid altogether
= 1.65 + 1.30
= $2.95
Answer(s): $2.95