Answer: 8.4
Explanation: Substitute y = 0.8 into the equation.
4x + 8(0.8) = 40
4x + 6.4 = 40
4x = 33.6
x = 8.4
Change the percentage to decimal
30% = 30/100 = 0.30
multiply the two numbers together
60 x 0.30 = 18
18 is your answer
hope this helps
x = number of 1-cent stamps
y = number of 8-cent stamps
z = number of 12-cent stamps
We have 31 stamps all together, so x+y+z = 31.
"I have 4 more 1-cent stamps than 8-cent stamps" means we have the equation x = y+8. Whatever y is, add 8 to it to get x. Solve for y to get y = x-8.
You also have "twice as many one cent stamps as 12 cent stamps", so x = 2z. Solving for z gets you z = 0.5x
-------------
x+y+z = 31
x+x-8+z = 31 ... y replaced with x-8
x+x-8+0.5x = 31 ... plug in z = 0.5x
2.5x-8 = 31
2.5x = 31+8
2.5x = 39
x = 39/2.5
x = 15.6
Your teacher made a typo somewhere because we should get a positive whole number result for x (since x is a count of how many 1-cent stamps we have).
Answer:
C)
Step-by-step explanation:
Because -8.2+(-4.1)=-8.2-4.1=-12.3.
