For the exponential equation
1 answer:
Answer:
Option: B is the correct answer.
B) Decay, y- intercept = 3.4, rate is 34%
Step-by-step explanation:
We are given an exponential equation as follows:
We know that any exponential function of the type:
is growth function if: b>1
and is a decay function if 0< b< 1
Hence, here we have: b=0.66<1
Hence, the function is a decay function.
Also, we know that the y-intercept of a function is the point where x=0
Hence, we take x=0
we have:
Hence, the y-intercept is: 3.4
Also, the rate of a function is denoted by 'r'
where b=1-r
⇒ 0.66=1-r
⇒ r=1-0.66
⇒ r=0.34
Hence, the rate is: 34%
option: B is the correct answer.
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Answer:
We conclude that there is no difference in the proportion of cockroaches that died on each surface.
Step-by-step explanation:
We are given that a study investigated the persistence of this pesticide on various types of surfaces.
After 14 days, they randomly assigned 72 cockroaches to two groups of 36, placed one group on each surface, and recorded the number that died within 48 hours. On the glass, 18 cockroaches died, while on plasterboard, 25 died.
<em>Let </em><em> = proportion of cockroaches that died on glass surface.</em>
<em /><em> = proportion of cockroaches that died on plasterboard surface.</em>
So, Null Hypothesis, :
= 0 {means that there is no difference in the proportion of cockroaches that died on each surface}
Alternate Hypothesis, :
0 {means that there is a significant difference in the proportion of cockroaches that died on each surface}
The test statistics that would be used here <u>Two-sample z proportion</u> <u>statistics</u>;
T.S. = ~ N(0,1)
where, = sample proportion of cockroaches that died on glass surface =
= 0.50
= sample proportion of cockroaches that died on plasterboard surface =
= 0.694
= sample of cockroaches on glass surface = 36
= sample of cockroaches on plasterboard surface = 36
So, <u><em>test statistics</em></u> =
= -1.712
The value of z test statistics is -1.712.
Since, in the question we are not given with the level of significance so we assume it to be 5%. Now, at 5% significance level the z table gives critical values of -1.96 and 1.96 for two-tailed test.
Since our test statistics lies within the range of critical values of z, so we have insufficient evidence to reject our null hypothesis as it will not fall in the rejection region due to which <u>we fail to reject our null hypothesis</u>.
Therefore, we conclude that there is no difference in the proportion of cockroaches that died on each surface.
Answer:
- the only possible value of x is 5
- the dimensions are 2 × 4 × 10
Step-by-step explanation:
The cubic equation ...
(x -3)(x -1)(x +5) = 80
has one real root: x = 5. Using that value for x, the dimensions become ...
length = 5 - 3 = 2
width = 5 - 1 = 4
height = 5 + 5 = 10
The dimensions are (length, width, height) = (2, 4, 10).
_____
We cannot tell the thrust of the problem, since it has only one solution. Perhaps you're supposed to write the cubic in standard form and use the <em>Rational Root theorem</em> to find <em>possible values of x</em>. That form can be found to be ...
(x -3)(x -1)(x +5) -80 = 0
x³ +x² -17x -65 = 0
Descartes' rule of signs tells you there is one positive real root. The rational root theorem tells you possible rational roots are factors of 65:
1, 5, 13, 65
We know that x must be greater than 3 (so all dimensions are positive). Thus <em>possible values of x are 5, 13, 65</em>, and we're pretty sure that 65 is way too large.
