Answer:
1. $450
2. $128
Step-by-step explanation:
1. new price = .4 (.4 * original price x)
72 = .16x
x = 450
2. new price = .75 (.75 * original price x)
72 = .5625x
x = 128
Answer:
Step-by-step explanation:
Let's call hens h and ducks d. The first algebraic equation says that 6 hens (6h) plus (+) 1 duck (1d) cost (=) 40.
The second algebraic equations says that 4 hens (4h) plus (+) 3 ducks (3d) cost (=) 36.
The system is
6h + 1d = 40
4h + 3d = 36
The best way to go about this is to solve it by substitution since we have a 1d in the first equation. We will solve that equation for d since that makes the most sense algebraically. Doing that,
1d = 40 - 6h.
Now that we know what d equals, we can sub it into the second equation where we see a d. In order,
4h + 3d = 36 becomes
4h + 3(40 - 6h) = 36 and then simplify. By substituting into the second equation we eliminated one of the variables. You can only have 1 unknown in a single equation, and now we do!
4h + 120 - 18h = 36 and
-14h = -84 so
h = 6.
That means that each hen costs $6. Since the cost of a duck is found in the bold print equation above, we will sub in a 6 for h to solve for d:
1d = 40 - 6(6) and
d = 40 - 36 so
d = 4.
That means that each duck costs $4.
ANSWER
1.39
EXPLANATION
The given quadratic equation is

This is the same as,

Comparing to

We have
a=2, b=3,c=-8
Using the quadratic formula, the solution is given by:

We substitute the values to get,


The positive root is

to the nearest hundredth.
Answer:
x^2+15x+7
Step-by-step explanation:
There are no like terms.
Answer:
B. 0.602%
Step-by-step explanation:
Probability is essentially (# times specific event will occur) / (# times general event will occur). Here, we have a few specific events: draw a quarter, draw a second quarter, draw a penny, and draw another penny. The general event will just be the number of coins there are to choose from.
The probability that the first draw is a quarter will be 4 / (4 + 8 + 9) = 4/21.
Since we've drawn one now, there's only 21 - 1 = 20 total coins left. The probability of drawing a second quarter is: (4 - 1) / (21 - 1) = 3/20.
The probability of drawing a penny is: 9 / (20 - 1) = 9/19.
The probability of drawing a second penny is: (9 - 1) / (19 - 1) = 8/18.
Multiply these four probabilities together:
(4/21) * (3/20) * (9/19) * (8/18) = 864 / 143640 ≈ 0.602%
The answer is B.