Answer:
56.42 minutes
Step-by-step explanation:
The initial sample= y0 = 800
After 13 minutes , amount = 320
Y= y0e-kt
320 = 800e-k(13)
320/800 = e-k13
0.4 = e-k13
In0.4 = -k13
-0.91629= -k13
0.07048= k
Y = 800e-0.07048t
Minutes when the bacterial present will be 15
15 = 800e-0.07048t
15/800= e-0.07048t
0.01875 = e-0.07048t
In 0.01875 = -0.07048t
-3.97656 = -0.07048t
-3.97656/-0.07048= t
56.42 = t
56.42 minutes
Line up the decimal points and multiply the rest like you would normally do it but drop down the decimal at the end
Answer:


Step-by-step explanation:
To solve this question we're going to use trigonometric identities and good ol' Pythagoras theorem.
a) Firstly, sec(θ)=52. we're gonna convert this to cos(θ) using:

we can substitute the value of sec(θ) in this equation:

and solve for for cos(θ)

side note: just to confirm we can find the value of θ and verify that is indeed an acute angle by
b) since right triangle is mentioned in the question. We can use:

we know the value of cos(θ)=1\52. and by comparing the two. we can say that:
- length of the adjacent side = 1
- length of the hypotenuse = 52
we can find the third side using the Pythagoras theorem.




- length of the opposite side = √(2703) ≈ 51.9904
we can find the sin(θ) using this side:


and since 

Answer:
15 miles
Step-by-step explanation:
If there are 2.5 inches and 1 inch is 6 miles, then just multiply 6 by 2.5 to get 15
6*2.5=15