2x+3(0)=18 2x=18 x=9
2(0)+3y=18 3y=18 y=6
The number of stamps and the cost are illustrations of unit rates
40 stamps would cost $22
The cost of 15 postage stamps is $8.25
Start by calculating the unit rate of the stamps.


So, the number of stamps for $22 is calculated by dividing $22 by the unit rate.
So, we have:


Hence, 40 stamps would cost $22
Read more about unit rates at:
brainly.com/question/396443
Answer:
OPTION B - 41
Step-by-step explanation:
An expression is given and the corresponding values for the expression are also given. We have to substitute the given values to arrive at the answer.
The given expression is: x + 3y + z.
Also given: x = 4, y = 5, z = 22.
Substitute these values in the above expression, we get:
4 + 3(5) + 22 = 4 + 15 + 22 = 41.
∴ x + 3y + z = 41
(r-s)/r=d would be the rule you use to find the discount when r= regular price and s equals sale price and d= discount