plz explain how to do this in detail:
using only 39 cent and 24 cent stamps, charlie put $7.14 postage on a package he mailed to his sister. if he used twice as many 39 cent stamps as 42 cent stampsp, how many 24 cent stamps did he use??
first represent the unknowns using variables:
let x = number of 24-cent stamps used
let 2x = number of 39-cent stamps used (according to the second statement)
since the total is 7.14 dollars,
0.24x + 0.39(2x) = 7.14
now we solve for x:
0.24x + 0.78x = 7.14
1.02x = 7.14
x = 7 (number of 24-cent stamps used)
hope this helps~ :)
Triple a number plus 7 results in 16. What is the number?
let x = number
according to the first statement, we multiply the number by three, then we add 7 to get 16,, writing in equation:
3x + 7 = 16
now solve for x,, first we transpose the 7 on the other side of equation,, to do this we change its sign from positive to negative:
3x = 16 - 7
3x = 9
to get x alone, we divide both side of equation by 3:
(3x)/3 = 9/3
x = 3
hope this helps~ :)
To solve this problem, we can break it down into smaller steps.
Step 1: Set up the equations.
Let's assume Charlie used x number of 39 cent stamps and y number of 24 cent stamps.
Step 2: Create the equation for the total value of the stamps used.
The total value of the stamps used can be obtained by multiplying the number of stamps by their respective values. In this case, the equation is:
0.39x + 0.24y = 7.14
Step 3: Create the equation for the number of stamps used.
We know that Charlie used twice as many 39 cent stamps as 24 cent stamps. So:
x = 2y
Step 4: Substitute the value of x from the second equation into the first equation.
Since we already have an equation for x in terms of y, we can substitute this value into the first equation:
0.39(2y) + 0.24y = 7.14
Simplifying this equation:
0.78y + 0.24y = 7.14
1.02y = 7.14
Step 5: Solve for y.
Divide both sides of the equation by 1.02:
y = 7.14 / 1.02
y ≈ 7
Step 6: Find the value of x.
Using the value of y, substitute it back into the second equation:
x = 2x 7
x = 14
Step 7: Verify the solution.
To check if our solution is correct, substitute the values of x and y into the first equation:
0.39(14) + 0.24(7) = 7.14
5.46 + 1.68 = 7.14
7.14 = 7.14
Therefore, Charlie used 14 of the 39 cent stamps (x) and 7 of the 24 cent stamps (y) to create $7.14 in postage on the package he mailed to his sister.