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Karo-lina-s [1.5K]
3 years ago
5

What expression is equivalent to 2.2-2.5?

Mathematics
2 answers:
Pani-rosa [81]3 years ago
4 0
Hi <span>Camrynb10705oxknsv!
So let's take a look at the answers they give. A is 2.5 - 2.2 and all that is is switching the numbers so that isn't right. B they do addition instead of subtraction so that can't be right. C they do 2.2 + (-2.5) and when you add a negative number it's like subtraction because a negative number is under 0 and so your adding a number under 0 so you go down. So the answer is C.
If you need me to explain it different let me know. Hope this helps!</span>
dybincka [34]3 years ago
4 0
The answer is C. How we know:
The origional expression would equate to -0.3
The reason A is incorrect is that you can not change the order of subtraction. This answer equates to 0.3.
The reason B is incorrect is that adding is not the same as subtracting. This answer equates to 4.7.
The reason D is incorrect is that subtracting a negative is the same as adding. This would equate to 4.7
The reason C is correct is that adding negative is the same as subtracting. This would equate to -0.3.
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The purple shape is a dilation of the black shape. Is it an enlargement or reduction?
Zarrin [17]
The answer is a enlargement
6 0
3 years ago
It is known that a particular laboratory task takes the average person 2.5 seconds. A researcher was interested in whether older
Alchen [17]

Answer:

 The decision rule is  

Fail to reject the null hypothesis

  The conclusion is

 There is no sufficient evidence to conclude that older people are slower

Step-by-step explanation:

From the question we are told that  

    The average time taken is  \mu =  2.5 \ seconds

      The  sample size is  n =  30

     The sample mean is  \= x =  2.7 \  seconds

      The standard deviation is  \sigma  =  1.4 \  seconds

The null hypothesis is  H_o:  \mu = 2.5

The alternative hypothesis  is  H_a :  \mu >  2.5 \  seconds

Generally the test statistics is mathematically represented as

                z =  \frac{\= x - \mu }{ \frac{\sigma }{ \sqrt{n} } }

=>              z =  \frac{ 2.7  -2.5 }{ \frac{1.4}{ \sqrt{30} } }

=>              z =  0.7825

From the z table  the area under the normal curve to the right corresponding to  0.7825   is  

                p-value  =  P(Z > 0.7825  ) =  0.21696

So from the question we see that the p-value  >  \alpha hence

 The decision rule is  

Fail to reject the null hypothesis

  The conclusion is

 There is no sufficient evidence to conclude that older people are slower

5 0
3 years ago
Help please I need it:
jonny [76]

Answer:

Step-by-step explanation:

The number of sandwiches sold: 73

The cost to make one sandwich: S

The profit the band earns from one sandwich: 0.2S

The amount of money that the band recieves for selling one sandwich:

S + 0.2S

6 0
3 years ago
Help answer the question please.
Reptile [31]

Answer:

49

Step-by-step explanation:

He recieved 8 ticket (even number) per day for 7 days. 8×7=56

56 tickets ÷ 7 days

would equal to him receiving 8 tickets every one of the 7 days.

7 0
3 years ago
Find the missing length
gregori [183]

Answer:

? = 55

Step-by-step explanation:

if we put the triangles onto of each other

side CT is on top of TR

126 ÷ 70 = 1.8

70 × 1.8 = 126

BT is on top of TS

so,

99 ÷ ? = 1.8

99 = 1.8 × ?

99 ÷ 1.8 = ?

55 = ?

55 × 1.8 = 99

Hoped i helped :)

7 0
3 years ago
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