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
The price:
- last year: $2.25
- this year: $.45
The decrease: $2.25 - $.45 = $1.80
2.25 : 1.80 = 100 : x
2.25 x = 180
x = 180 : 2.25
x = 80
Answer:
The percent of decrease is A ) 80%
You have to multiply 3 x 6.
The answer to question 34:
Let 'x' = pounds of gravel. The ratio of mulch to gravel is given 2 1/4 | 1 1/3. Which equals 9/4 | 4/3 = 27/16.
So the total gravel and much is equal to x + 27/16x = 172
Solving for 'x'
43/16 x = 172
x = 172 (16/43) = 64 pounds of gravel Mulch = 27/16x = 64 (27/16)= 108 pounds
The answer to question 35:
A.) 1,080 beats per minute at rest and 1,500 beats per minute while running.
B.) 4,500 (while running) - 3,240 (at rest) = 1,260 more beats while running than at rest.
