9x-30 I’m pretty sure!
We are finding the difference, which means subtract! Nine times a number would be 9x and since it’s difference you would subtract it by 30.
Answer:
Billie's age = x = 17 years
Tony's age = y = 31 years
Step-by-step explanation:
Let
Billie's age = x
Tony's age = y
Twice Billie’s age decreased by 3 is Tony’s age.
y = 2x - 3..... Equation 1
Tony is fourteen years older than Billie.
x = y - 14
We substitute y - 14 for x in Equation 1
y = 2x - 3..... Equation 1
y = 2(y - 14) - 3
y = 2y - 28 - 3
y - 2y = -28 - 3
-y = -31
y = 31 years
Solving for x
x = y - 14
x = 31 - 14
x = 17 years.
Therefore:
Billie's age = x = 17 years
Tony's age = y = 31 years
Answer:
(a) 13.85 °C
Step-by-step explanation:
The temperature difference is a decaying exponential function of time. Here, it decreases from an initial difference of 15 °C to 10 °C after 25 minutes. So, that temperature difference can be modeled as ...
ΔT = 15(10/15)^(t/25)
We want to find the value of this at t=55. It is ...
ΔT = 15(2/3)^(55/25) ≈ 6.15
This is the amount the temperature of the drink is below room temperature.
drink temperature = (20 - 6.15) °C = 13.85 °C
The temperature of the drink after 55 minutes is about 13.85 °C.
Sorry what is the question I cannot see the question
Answer:
20
Step-by-step explanation:
if you want a explanation ask for it :)
