For the first digit, you have two possible choices: 1 or 2. For *each* of those choices, you can choose 1 or 2 for the second digit in the number, and for each of *those*, you can choose 1 or 2 for the third digit of the number.
That’s 2 * 2 * 2 or 8 possible 3-digit numbers you can make with the digits 1 and 2.
9514 1404 393
Answer:
Step-by-step explanation:
The decay factor is 1 -25% = 0.75 per hour, so the exponential equation can be written ...
r(t) = 1450·0.75^t . . . . . milligrams remaining after t hours
__
a) After 4 hours, the amount remaining is ...
r(4) = 1450·0.75^4 ≈ 458.79 . . . mg
About 459 mg will remain after 4 hours.
__
b) To find the time it takes before the amount remaining is less than 5 mg, we need to solve ...
r(t) < 5
1450·0.75^t < 5 . . . . use the function definition
0.75^t < 5/1450 . . . . divide by 1450
t·log(0.75) < log(1/290) . . . . . take logarithms (reduce fraction)
t > log(1/290)/log(0.75) . . . . . divide by the (negative) coefficient of t
t > 19.708
It will take about 20 hours for the amount of the drug remaining to be less than 5 mg.
Answer:
6
out of the total donuts (90), Ryan ate 12 cream filled donuts. 45 is half of that, therefore he should eat half the cream filled donuts
Answer:
1.28 m
Step-by-step explanation:
The speed at which water rises in the tank is proportional to the speed of the water in the pipe and inversely proportional to the ratio of the tank area to the pipe area.
The ratio of tank area to pipe area is the square of the ratio of their diameters:
((150 cm)/(4 cm))² = 1406.25
Then the rate of rise of water in the tank is ...
(0.5 m/s)/(1406.25)
After 1 hour = 3600 seconds, the height of the water will be ...
rise = (time)(rate of rise)
(3600 s)(0.5 m/s)/1406.25 = 1.28 m