Answer:
n=10
Step-by-step explanation:
5n-20=3n
-20=-2n
10=n
Newton's Law of Cooling
Tf=Ts+(Ti-Ts)e^(-kt) where Tf is temp at time t, Ts is temp of surroundings, Ti is temp of object/fluid. So we need to find k first.
200=68+(210-68)e^(-10k)
132=142e^(-10k)
132/142=e^(-10k)
ln(132/142)=-10k
k=-ln(132/142)/10
k≈0.0073 so
T(t)=68+142e^(-0.0073t) so how long until it reaches 180°?
180=68+142e^(-0.0073t)
112=142e^(-0.0073t)
112/142=e^(-0.0073t)
ln(112/142)=-0.0073t
t= -ln(112/142)/(0.0073)
t≈32.51 minutes
Answer:
x is 20
Step-by-step explanation:
Answer:
B 12
Step-by-step explanation:
- manuel ate 1/3X
- His brother ate 1/4X
- leftover is 5
- total is X
manuel+brother+leftover=X
x/3+x/4+5=x
7x+60/12=x
7x+60=12x
60=12x-7x
60=5x
x=60/5
x= 12
