1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
nignag [31]
3 years ago
7

Sarah needs to go to five different stores. How many ways can she go to two of them before lunch?

Mathematics
1 answer:
Zina [86]3 years ago
6 0

Answer:

10

Step-by-step explanation:

Solution 1: At first, you might think that because there are 5 ways to choose the first store and 4 ways to choose the second store, the answer is 5 * 4 = 20 but this is over-counting by a factor of 2. Say that two of the stores are A and B. If she went to A then B, that's the same as going to B then A since you still go to the same stores, therefore, the answer is 20 / 2 = 10.

Solution 2: We need to find the number of ways to choose 2 stores from 5, we can do this by calculating ₅C₂ which equals:

5! / 2!  * 3!

= 5 * 4 * 3 * 2 * 1 / 2 * 1 * 3 * 2 * 1

= 5 * 4 / 2 * 1

= 10

You might be interested in
The concentration C (in mg/dl), of an antibiotic in a patient’s bloodstream per hour, t, is given by: c(t) = (50t)/(t^2+25) In o
NARA [144]

Answer:

Step-by-step explanation:

<u>Functions </u>

The problem describes a function that expresses the concentration of an antibiotic in mg/dl vs time in hours as:

\displaystyle c(t)=\frac{50\ t}{t^2+25}

We need to find the first value of t such that

\displaystyle c(t)\geq 4

It means that

\displaystyle \frac{50\ t}{t^2+25}\geq 4

Operating with the inequality

\displaystyle 50\ t\geq 4\ t^2+100

Rearranging and dividing by 2, we have a polynomial inequality:

\displaystyle 2t^2-25t+50\leq 0

Factoring

\displaystyle 2(t-10)\left (t-\frac{5}{2}\right )\leq 0

There are two possible values for t, both valids because they are positive

\displaystyle t=\frac{5}{2}=2.5, \ t=10

We need to find the first value, i.e.

t=2.5 \ hours

Now for the graphic method, we plot the graph for the function and a horizontal line at c=4 to find the values of t.

The graph is shown in the image provided below. We can see both values where the funcion and C=4 intersect. Both values coincide with the previously analitically found values

4 0
4 years ago
39y³(50y² - 98) ÷26y²5y + 7)​
olga nikolaevna [1]

Answer:

3y5 • (5y + 7)2 • (5y - 7) then solve that which is (3•2y5) • (5y + 7) • (5y - 7) and keep going { 3x−2y=5 & 2x−5y=7

SOLVE FOR X, Y

x=1

y=−1

I hope this helps a little

7 0
2 years ago
The equation of a parabola is y=x2+6x+9. Write the equation in vertex form.
nignag [31]

Answer:

Step-by-step explanation:

Vertex form is accomplished by completing the square on the quadratic. Do this by first setting the parabola equal to 0 then moving the constant over to the other side:

x^2+6x=-9

Now take half the linear term, square it, and add it to both sides. Our linear term is 6. Half of 6 is 3, and 3 squared is 9:

x^2+6x+9=-9+9

The reason we do this is to create a perfect square binomial on the left:

(x+3)^2=0 (obviously the 0 results from the addition of 9 and -9). Move the 0 back over to the other side and set the quadratic back equal to y:

(x+3)^2+0=y

This gives you a vertex of (-3, 0), which is a minimum value, since the parabola opens upwards.

6 0
3 years ago
Write a word porblem that could be solved with the equation x - 3/4 = 6 3/4
Amanda [17]

Answer:

use ph0t03ath or m4th3ay

7 0
3 years ago
Frank has a cupboard for his books and toys. The cupboard is split into 6 parts. 1 part is for keeping his books and notebooks.
konstantin123 [22]

Answer:

1/6 ÷2

1/12

Step-by-step explanation:

1 cabinet is divided into 6 parts. He splits 1 part of the 6 in half

1 ÷6 ÷ 2

1/6 ÷2

Copy dot flip

1/6 * 1/2

1/12

3 0
3 years ago
Read 2 more answers
Other questions:
  • What is the density of a block with a mass of 420 g and a length of 2cm, 3cm wide, and 1cm long​
    8·1 answer
  • Budget
    7·1 answer
  • Using synthetic division, find (x^4 − 2) ÷ (x + 1).
    11·1 answer
  • If the associated linear function of this sequence was graphed, what would be its slope?
    9·1 answer
  • X2 + 8xz + x + 8z<br><br> I NEED HELP FACTORING THIS
    5·1 answer
  • According to the pedometer i move 27 5/8 inches when i walk How many feet i will travel in 96 steps?
    15·1 answer
  • Classify each triangle by its angle and by it sides
    10·1 answer
  • A 2-pound bag of broccoli costs $4.48. What is the price per ounce?
    8·2 answers
  • Question 3
    14·1 answer
  • URGENT!!!!!
    8·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!