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Yuliya22 [10]
4 years ago
6

Ten teaching assistants are available for grading papers in a particular course. The first exam consists of four questions, and

the professor wishes to select a different assistant to grade each question (only one assistant per question). In how many ways can assistants be chosen to grade the exam
Mathematics
1 answer:
nydimaria [60]4 years ago
5 0

Answer:

There are 210 ways

Step-by-step explanation:

The number of ways or combinations in which we can select x elements from a group of n elements where the order doesn't matter can be calculated as:

nCx=\frac{n!}{x!(n-x)!}

So, we have 10 teaching assistants and we need to choose 4 (one assistant per question) to grade each question. It means that n is equal to 10 and x is equal to 4.

Therefore, the number of ways that the assistants can be chosen to grade the exam are calculated as:

10C4=\frac{10!}{4!(10-4)!}=210

You might be interested in
Give the rate in miles per hour. Round to the nearest tenth.<br> Rachel jogs 20 feet in 3 seconds.
Tanya [424]

Answer:

Rate of jogging is 4.6 miles per hour.

Step-by-step explanation:

Rachel jogs 20 feet in 3 seconds and we have to find the rate of jogging in miles per hour.

Since 1 feet = 0.000189394 miles

Therefore, 20 feet = 0.0037879 miles

Similarly, 1 second = \frac{1}{3600} hour

Therefor, 3 seconds = \frac{3}{3600}

                                  = \frac{1}{1200} hours

Formula to calculate the rate = \frac{\text{Total distance of jogging}}{\text{Time taken to cover the distance}}

                                                = \frac{0.0037879}{\frac{1}{1200} }                                                        

                                                = 1200 × 0.0037879

                                                = 4.545

                                                ≈ 4.6 miles per hour

Therefore, rate of jogging is 4.6 miles per hour.

6 0
3 years ago
Laura lleno su pecera hasta la mitad 40 cm 60 cm 20 cm cuanto espacio ocupa la pecera
Anvisha [2.4K]
B 100


MThat’s the answer
6 0
3 years ago
Can i get some help with #5 please
Sidana [21]
 a = 6, is your answer.

Square both sides
<span><span><span>9=a−2<span>(6−a)(2a−3)</span>+3</span>9=a-2\sqrt{(6-a)(2a-3)}+3</span><span>9=a−2<span>√<span><span>​<span>(6−a)(2a−3)</span></span>​<span>​​</span></span></span>+3

</span></span>2 .Separate terms with roots from terms without roots
<span><span><span>9−a−3=−2<span>(6−a)(2a−3)</span></span>9-a-3=-2\sqrt{(6-a)(2a-3)}</span><span>9−a−3=−2<span>√<span><span>​<span>(6−a)(2a−3)
</span></span>​<span>​​</span></span></span></span></span>
3. Simplify <span><span><span>9−a−3</span>9-a-3</span><span>9−a−3</span></span> to <span><span><span>6−a</span>6-a</span><span>6−a
</span></span><span><span><span>6−a=−2<span>(6−a)(2a−3)</span></span>6-a=-2\sqrt{(6-a)(2a-3)}</span><span>6−a=−2<span>√<span><span>​<span>(6−a)(2a−3)
</span></span>​<span>​​</span></span></span></span></span>
4 .Square both sides
<span><span><span><span><span>(6−a)</span>2</span>=4(6−a)(2a−3)</span>{(6-a)}^{2}=4(6-a)(2a-3)</span><span><span><span>(6−a)</span><span><span>​2</span><span>​​</span></span></span>=4(6−a)(2a−3)

</span></span>5 .Expand
<span><span><span>36−12a+<span>a2</span>=48a−72−8<span>a2</span>+12a</span>36-12a+{a}^{2}=48a-72-8{a}^{2}+12a</span><span>36−12a+<span>a<span><span>​2</span><span>​​</span></span></span>=48a−72−8<span>a<span><span>​2</span><span>​​</span></span></span>+12a

</span></span>6. Simplify <span><span><span>48a−72−8<span>a2</span>+12a</span>48a-72-8{a}^{2}+12a</span><span>48a−72−8<span>a<span><span>​2</span><span>​​</span></span></span>+12a</span></span> to <span><span><span>60a−72−8<span>a2</span></span>60a-72-8{a}^{2}</span><span>60a−72−8<span>a<span><span>​2</span><span>​​</span></span></span></span></span>
<span><span><span>36−12a+<span>a2</span>=60a−72−8<span>a2</span></span>36-12a+{a}^{2}=60a-72-8{a}^{2}</span><span>36−12a+<span>a<span><span>​2</span><span>​​</span></span></span>=60a−72−8<span>a<span><span>​2
</span><span>​​</span></span></span></span></span>
7. Move all terms to one side
<span><span><span>36−12a+<span>a2</span>−60a+72+8<span>a2</span>=0</span>36-12a+{a}^{2}-60a+72+8{a}^{2}=0</span><span>36−12a+<span>a<span><span>​2</span><span>​​</span></span></span>−60a+72+8<span>a<span><span>​2</span><span>​​</span></span></span>=0

</span></span>8. Simplify <span><span><span>36−12a+<span>a2</span>−60a+72+8<span>a2</span></span>36-12a+{a}^{2}-60a+72+8{a}^{2}</span><span>36−12a+<span>a<span><span>​2</span><span>​​</span></span></span>−60a+72+8<span>a<span><span>​2</span><span>​​</span></span></span></span></span> to <span><span><span>36−72a+9<span>a2</span>+72</span>36-72a+9{a}^{2}+72</span><span>36−72a+9<span>a<span><span>​2</span><span>​​</span></span></span>+72</span></span>
<span><span><span>36−72a+9<span>a2</span>+72=0</span>36-72a+9{a}^{2}+72=0</span><span>36−72a+9<span>a<span><span>​2</span><span>​​</span></span></span>+72=0

</span></span>9 .Simplify <span><span><span>36−72a+9<span>a2</span>+72</span>36-72a+9{a}^{2}+72</span><span>36−72a+9<span>a<span><span>​2</span><span>​​</span></span></span>+72</span></span> to <span><span><span>−72a+9<span>a2</span>+108</span>-72a+9{a}^{2}+108</span><span>−72a+9<span>a<span><span>​2</span><span>​​</span></span></span>+108</span></span>
<span><span><span>−72a+9<span>a2</span>+108=0</span>-72a+9{a}^{2}+108=0</span><span>−72a+9<span>a<span><span>​2</span><span>​​</span></span></span>+108=0

</span></span>10.Factor out the common term <span><span>99</span>9</span>
<span><span><span>−9(8a−<span>a2</span>−12)=0</span>-9(8a-{a}^{2}-12)=0</span><span>−9(8a−<span>a<span><span>​2</span><span>​​</span></span></span>−12)=0

</span></span>11. Factor out the negative sign
<span><span><span>−9×−(<span>a2</span>−8a+12)=0</span>-9\times -({a}^{2}-8a+12)=0</span><span>−9×−(<span>a<span><span>​2</span><span>​​</span></span></span>−8a+12)=0

</span></span>12. Divide both sides by <span><span><span>−9</span>-9</span><span>−9</span></span>
<span><span><span>−<span>a2</span>+8a−12=0</span>-{a}^{2}+8a-12=0</span><span>−<span>a<span><span>​2</span><span>​​</span></span></span>+8a−12=0

</span></span>13. Multiply both sides by <span><span><span>−1</span>-1</span><span>−1</span></span>
<span><span><span><span>a2</span>−8a+12=0</span>{a}^{2}-8a+12=0</span><span><span>a<span><span>​2</span><span>​​</span></span></span>−8a+12=0

</span></span>14. Factor <span><span><span><span>a2</span>−8a+12</span>{a}^{2}-8a+12</span><span><span>a<span><span>​2</span><span>​​</span></span></span>−8a+12</span></span>
<span><span><span>(a−6)(a−2)=0</span>(a-6)(a-2)=0</span><span>(a−6)(a−2)=0

</span></span>15. Solve for <span><span>aa</span>a</span>
<span><span><span>a=6,2</span>a=6,2</span><span>a=6,2

</span></span>16 Check solution
When <span><span><span>a=2</span>a=2</span><span>a=2</span></span>, the original equation <span><span><span>−3=<span>6−a</span>−<span>2a−3</span></span>-3=\sqrt{6-a}-\sqrt{2a-3}</span><span>−3=<span>√<span><span>​<span>6−a</span></span>​<span>​​</span></span></span>−<span>√<span><span>​<span>2a−3</span></span>​<span>​​</span></span></span></span></span> does not hold true.
We will drop <span><span><span>a=2</span>a=2</span><span>a=2</span></span> from the solution set.

17. Therefore,
<span><span><span>a=6</span></span><span /></span>


5 0
3 years ago
Melanie used 864 beads to make 5 bracelets put the .she put the same number of beads on each bracelet. How many beads does each
Yanka [14]

Answer:

172

Step-by-step explanation:

864 / 5 = 172.8

And so there cant' be a half of a bead, so thre is 172.

7 0
3 years ago
Which answer is it? Plz show work
Vesnalui [34]
Your answer would be B
5 0
3 years ago
Read 2 more answers
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