Let p = number of pennies.
Let n = number of nickels.
We are given that n= 2p and the total value is $8.80.
We know that a penny = $0.01 and that a nickel = $0.05.
So $0.01p + $0.05n = $8.80.
Substitute 2p for n:
$0.01p + $0.05*2p = $8.80
$0.01p + $0.10p = $8.80
$0.11p = $8.80
p = 80
So n = 2p = 2*80 = 160
Thus there are 80 pennies ($0.8) and 160 nickels ($8.00). The value of all the coins is $8.80.
Answer:
1.5 mph
Step-by-step explanation:
Let speed of boat be x
let speed of current be c
Also, note D = RT
D is distance
R is rate
T is time
Now, for first leg, we can write:
(x+c)3 = D
And for second leg , we can write:
(x-c)4.8 = D [note 4 hour 48 minutes is 4.8 hours]
We can equate both D's to get:
(x+c)3 = (x-c)4.8
3x + 3c = 4.8x - 4.8c
7.8c = 1.8x
We know x = 6.5 [given], plugging it in and solving for c:
7.8c = 1.8(6.5)
c = 1.5
Speed of Current = 1.5 miles per hour
Printer A
y = 14x
Printer B
Time(min) | 3 | 5 | 8 | 12 |
Pages printed | 48 | 80 | 128 | 192 |
Printer A prints 14(1) = 14 pages per minute.
Printer B prints 48/3 = 16 pages per minute.
The printer that prints at a faster rate is printer B.
Answer:
x = 5
Step-by-step explanation:
Step 1: Write equation
-3/4 + 2/5x = 7/20x - 1/2
Step 2: Subtract 7/20x on both sides
-3/4 + 1/20x = -1/2
Step 3: Add 3/4 to both sides
1/20x = 1/4
Step 4: Divide 1/20 on both sides
x = 5
Answer:
3.85 hours
Step-by-step explanation:
We have that the model equation in this case would be of the following type, being "and" the concentration of bacteria:
y = a * e ^ (b * t)
where a and b are constants and t is time.
We know that when the time is 0, we know that there are 100,000 bacteria, therefore:
100000 = a * e ^ (b * 0)
100000 = a * 1
a = 100000
they tell us that when the time is 2 hours, the amount doubles, that is:
200000 = a * e ^ (b * 2)
already knowing that a equals 100,000
e ^ (b * 2) = 2
b * 2 = ln 2
b = (ln 2) / 2
b = 0.3465
Having the value of the constants, we will calculate the value of the time when there are 380000, that is:
380000 = 100000 * (e ^ 0.3465 * t)
3.8 = e ^ 0.3465 * t
ln 3.8 = 0.3465 * t
t = 1.335 / 0.3465
t = 3.85
That is to say that in order to reach this concentration 3.85 hours must pass
