Use the permutation formula
nPr = (n!)/((n-r)!)
20P15 = (20!)/((20-15)!)
20P15 = (20!)/(5!)
The final answer is choice A
Subtract to find the amount of the increase:
168 - 140 = 28
The increase in price was $28.
Now divide the amount of increase by the original price.
This will give you a decimal, then multiply the decimal by 100 to get the percent:
28 / 140 = 0.2
0.2 x 100 = 20% increase.
Answer:
Prob because you were giving away free points or broke the rules.
Answer:
I could do 1 and 3
1) 2x-3y=-2 ....1
-
2x+y=14......2
=-4y=-16
y=4
<u>Substitute</u><u> </u><u>(</u><u>y</u><u>=</u><u>4</u><u>)</u><u> </u><u>into</u><u> </u><u>equation</u><u> </u><u>1</u>
2x-3 (4)=-2
2x-12=-2
2x=-2+12
2x=10
×=5
3) 5x+5y=20....1
-
-3x+5y=4......2
=8x=16
x=2
<u>S</u><u>ubstitute</u><u> </u><u>(</u><u>x</u><u>=</u><u>2</u><u>)</u><u> </u><u>into</u><u> </u><u>equation</u><u> </u><u>1</u>
<u>5</u><u> </u><u>(</u><u>2</u><u>)</u><u>+</u><u>5y</u><u>=</u><u>20</u>
<u>10</u><u>+</u><u>5y</u><u>=</u><u>20</u>
<u>5y</u><u>=</u><u>20-10</u>
<u>5y</u><u>=</u><u>10</u>
<u>y</u><u>=</u><u>2</u>
X² - 3x - 10
x² = x * x
10 can be factored:
1 x 10 ⇒⇒⇒ difference between factors = 9
2 x 5 ⇒⇒⇒ difference between factors = 3 ⇒ (The correct pair)
(x-5)(x+2) = x(x+2) - 5(x+2)
= x² + 2x - 5x - 10
= x² - 3x - 10
∴ x - 5 = 0 ⇒⇒⇒ x = 5
x + 2 = 0 ⇒⇒⇒ x = -2
