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3 years ago

14

a shirt is on sale for $25 at the local department store the sales tax equal 1/25 of the shirt's price. What is the total cost o

f the shirt including sales tax

1 answer:

stellarik [79]3 years ago

4 0

The shirt will cost $26.

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Need help with this please or explain how to solve it

Aloiza [94]

Answer:

B The cost to use the service for one month if zero songs are downloaded

4 0

3 years ago

Solve the following equation for y, and then identify the slope of the line: 9x-3y=15

sashaice [31]

$9x-3y=15\ \ \ | subtract\ 9x\\\\
-3y=-9x+15\ \ \ | divide\ by\ -3\\\\
y=3x-5\\\\
y=ax+b\ \ a-\ slope\\\\
a=3\\\\Slope\ is\ equal\ to\ 3.$

5 0

3 years ago

Read 2 more answers

Prove or disprove (from i=0 to n) sum([2i]^4) <= (4n)^4. If true use induction, else give the smallest value of n that it doe

ddd [48]

Answer:

The statement is true for every n between 0 and 77 and it is false for $n\geq 78$

Step-by-step explanation:

First, observe that, for n=0 and n=1 the statement is true:

For n=0: $\sum^{n}_{i=0} (2i)^4=0 \leq 0=(4n)^4$

For n=1: $\sum^{n}_{i=0} (2i)^4=16 \leq 256=(4n)^4$

From this point we will assume that $n\geq 2$

As we can see, $\sum^{n}_{i=0} (2i)^4=\sum^{n}_{i=0} 16i^4=16\sum^{n}_{i=0} i^4$ and $(4n)^4=256n^4$ . Then,

$\sum^{n}_{i=0} (2i)^4 \leq(4n)^4 \iff \sum^{n}_{i=0} i^4 \leq 16n^4$

Now, we will use the formula for the sum of the first 4th powers:

$\sum^{n}_{i=0} i^4=\frac{n^5}{5} +\frac{n^4}{2} +\frac{n^3}{3}-\frac{n}{30}=\frac{6n^5+15n^4+10n^3-n}{30}$

Therefore:

$\sum^{n}_{i=0} i^4 \leq 16n^4 \iff \frac{6n^5+15n^4+10n^3-n}{30} \leq 16n^4 \\\\ \iff 6n^5+10n^3-n \leq 465n^4 \iff 465n^4-6n^5-10n^3+n\geq 0$

and, because $n \geq 0$ ,

$465n^4-6n^5-10n^3+n\geq 0 \iff n(465n^3-6n^4-10n^2+1)\geq 0 \\\iff 465n^3-6n^4-10n^2+1\geq 0 \iff 465n^3-6n^4-10n^2\geq -1\\\iff n^2(465n-6n^2-10)\geq -1$

Observe that, because $n \geq 2$ and is an integer,

$n^2(465n-6n^2-10)\geq -1 \iff 465n-6n^2-10 \geq 0 \iff n(465-6n) \geq 10\\\iff 465-6n \geq 0 \iff n \leq \frac{465}{6}=\frac{155}{2}=77.5$

In concusion, the statement is true if and only if n is a non negative integer such that $n\leq 77$

So, 78 is the smallest value of n that does not satisfy the inequality.

Note: If you compute $(4n)^4- \sum^{n}_{i=0} (2i)^4$ for 77 and 78 you will obtain:

$(4n)^4- \sum^{n}_{i=0} (2i)^4=53810064$

$(4n)^4- \sum^{n}_{i=0} (2i)^4=-61754992$

7 0

3 years ago

John is throwing a dart at a dartboard. There are 4 rings that surround the bull's-eye ring,

barxatty [35]

1/19 because the rings would be 1,3,4,5,6 respectively and then u add it up

3 0

2 years ago

A gift shop wants to make gift baskets for its regular customers. There are 24 bottles

Nuetrik [128]

Answer:

Find the biggest # that can divide all 3 #'s, and that's your answer.

Step-by-step explanation:

24 is divisible by:

1, 2, 3, 4, 6, 8, 12, 24

36 is divisible by:

1, 2, 3, 4, 6, 9, 12, 18, 36

48 is divisible by:

1, 2, 3, 4, 6, 8, 12, 16, 24, 48

The biggest # that can divide all 3 #'s is 12, so the greatest amount of baskets that can be made is 12 baskets.

6 0

2 years ago