The temperature was -14°F at 8 a.m.
At noon is was 10 degrees warmer - the temperature increase was 10°F
-14°F + 10°F = -4°F
The tempertaure increase between noon and 4 p.m. was twice the previous increase in temperature, which was 10°F.
10°F x 2 = 20°F
We want to know the temperature at 4 p.m. so we just add it up to the previous result.
-4°F + 20°F = 16°F
16°F is the correct answer
Answer:
Julie need to sell at least 45 shirts to break even.
Step-by-step explanation:
The selling cost of each shirt = $ 20
Cost of each shirt = $6
The fixed cost per month = $420
Number of shirts she can make = 80
Hence, the <u>cost of making 80 shirts</u> = 80 x $6 = $480
So, her total capital investment of the month
= Cost of shirts made + Fixed cost = $420 + $480 = $900
Now, let us assume she sell k number of shirts.
⇒ $20 x k = $900
or, k = 900 / 20 = 45
or, k = 45
Hence, Julie need to sell at least 45 shirts to break even.
Answer: You need to wait at least 6.4 hours to eat the ribs.
t ≥ 6.4 hours.
Step-by-step explanation:
The initial temperature is 40°F, and it increases by 25% each hour.
This means that during hour 0 the temperature is 40° F
after the first hour, at h = 1h we have an increase of 25%, this means that the new temperature is:
T = 40° F + 0.25*40° F = 1.25*40° F
after another hour we have another increase of 25%, the temperature now is:
T = (1.25*40° F) + 0.25*(1.25*40° F) = (40° F)*(1.25)^2
Now, we can model the temperature at the hour h as:
T(h) = (40°f)*1.25^h
now we want to find the number of hours needed to get the temperature equal to 165°F. which is the minimum temperature that the ribs need to reach in order to be safe to eaten.
So we have:
(40°f)*1.25^h = 165° F
1.25^h = 165/40 = 4.125
h = ln(4.125)/ln(1.25) = 6.4 hours.
then the inequality is:
t ≥ 6.4 hours.
