Please solve these coin problems:

1. James bought 80 postage stamps for which he paid $18.40. Some were 1 cent stamps and some were 33 cent stamps. How many of each kind did he buy?

2. A postal clerk sold 75 stamps for $19.90. Some were 20 cent stamps and some were 34 cent stamps. How many of each kind did he sell?

Solving from system of equations: x- amount of 1 cent stamps y- amount of 33 cent stamps { x + y = 80 1 ∗ x + 33 ∗ y = 18 , 40 ​ x = 80 − y 0 , 01 ∗ ( 80 − y ) + 0 , 33 y = 18 , 40 0 , 8 − 0 , 01 y + 0 , 33 y = 18 , 40 0 , 32 y = 18 , 40 − 0 , 8 0 , 32 y = 17 , 60/ : 0 , 32 y = 55 x = 80 − 55 = 25
x- amount of 20 cent stamops y-amount of 34 cent stamps From system of equations: { x + y = 75 0 , 2 x + 0 , 34 y = 19 , 90 ​ x = 75 − y 0 , 2 ( 75 − y ) + 0 , 34 y = 19 , 90 15 − 0 , 2 y + 0 , 34 y = 19 , 90 − 0 , 2 y + 0 , 34 y = 19 , 90 − 15 0 , 14 y = 4 , 90/ : 0 , 14 y = 35 x = 75 − 35 = 40

Answered by luana | 2024-06-10

James bought 25 one-cent stamps and 55 thirty-three cent stamps. The postal clerk sold 40 twenty-cent stamps and 35 thirty-four cent stamps.
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Answered by luana | 2024-10-01