PSLE The airmail rates to two countries are shown. Usha sent a letter weighing 53g to Vietnam and a letter weighing 16g to New Zealand by airmail. How much did she pay altogether?
Mass |
Vietnam |
New Zealand |
First 20g |
$0.75 |
$1.60 |
Every additional 10g |
$0.55 |
$0.70 |
Mass of the letter to Vietnam excluding the first 20 g
= 53 - 20
= 33 g
Sets of additional 10 g of the letter to Vietnam
= 33 ÷ 10
= 3 r 3
Sets of additional 10 g and part thereof the letter to Vietnam
= 3 + 1
= 4
Amount that Usha paid for the letter to Vietnam
= 0.75 + 4 x 0.55
= 0.75 + 2.20
= $2.95
Amount that Usha paid altogether
= 2.95 + 1.60
= $4.55
Answer(s): $4.55