You would do 2x-3+x+3x-15=360
combine like terms which then gives you
5x-18=360 then you would add 18 to both sides giving you
5x=378
and then you divide by 5 on both sides which will then give you your answer x=?
Because thats not how its pronounced anymore.
Happy studying ^_^
Answer:
We need to sample at least 1069 parents.
Step-by-step explanation:
We have that to find our
level, that is the subtraction of 1 by the confidence interval divided by 2. So:

Now, we have to find z in the Ztable as such z has a pvalue of
.
So it is z with a pvalue of
, so 
Now, find the margin of error M as such

In which
is the standard deviation of the population and n is the size of the sample.
How many parents do you have to sample?
We need to sample at least n parents.
n is found when
. So






Rounding up
We need to sample at least 1069 parents.
Multiply 4 by 10%.
10% ⇒ 0.1
4 × 0.1 = 0.4
Subtract 0.4 from 4.
4 - 0.4 = 3.6 (price with discount)
Multiply 3.6 by 6%.
6% ⇒ 0.06
3.6 × 0.06 = 0.216
Add 0.216 to 3.6.
0.216 + 3.6 = 3.816
Round 3.816 to the hundredths.
3.816 ⇒ 3.82 (price with tax)
The new price of toothbrushes is $3.82.