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3 years ago

Find three consecutive numbers whose sum is 219

Mathematics

2 answers:

LenaWriter [7]3 years ago

8 0

72, 73, 74 is the answer.

Romashka [77]3 years ago

7 0

Answer:

72, 73, 74

Step-by-step explanation:

x + x+ 1 + x + 2

3x+3=219

subtract 3

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A new car sells for $27,500. The value of the car decreases by 14% annually. You want to sell the car when it's worth about $400

NemiM [27]

Answer: 13 years.

Step-by-step explanation:

The price decreases by 14% anually

To find the decimal form, you have 14%/100% = 0.14

So, the year zero, the price is $27,500

After one year, the price is:

P = $27,500 - 0.14*$27500 = $27,500*(0.86)

After the second year, the price is:

P = $27,500*(0.86)^2

and so on, so we want to find x such that:

P = $27,500*(0.86)^x = $4000

0.86^x = $4000/$27,500

Now, using the natural logaritm rule:

a^x = b

x = ln(a)/ln(b)

x = ln($4000/$27,500)/ln(0.86) = 12.8

We can round it up to 13, so after 13 years the price of the car is about $4000

7 0

3 years ago

Use <,>,or= to compare the ratios 36 ? 6 <br> 60 10

katen-ka-za [31]

Answer:

36/60 =6/10

Step-by-step explanation:

36/60 = 0.6

6/10=0.6

4 0

3 years ago

The first, third and thirteenth terms of an arithmetic sequence are the first 3 terms of a geometric sequence. If the first term

Salsk061 [2.6K]

Answer:

The first three terms of the geometry sequence would be $1$ , $5$ , and $25$ .

The sum of the first seven terms of the geometric sequence would be $127$ .

Step-by-step explanation:

Let $d$ denote the common difference of the arithmetic sequence.

Let $a_1$ denote the first term of the arithmetic sequence. The expression for the $n$ th term of this sequence (where $n\!$ is a positive whole number) would be $(a_1 + (n - 1)\, d)$ .

The question states that the first term of this arithmetic sequence is $a_1 = 1$ . Hence:

The third term of this arithmetic sequence would be $a_1 + (3 - 1)\, d = 1 + 2\, d$ .
The thirteenth term of would be $a_1 + (13 - 1)\, d = 1 + 12\, d$ .

The common ratio of a geometric sequence is ratio between consecutive terms of that sequence. Let $r$ denote the ratio of the geometric sequence in this question.

Ratio between the second term and the first term of the geometric sequence:

$\displaystyle r = \frac{1 + 2\, d}{1} = 1 + 2\, d$ .

Ratio between the third term and the second term of the geometric sequence:

$\displaystyle r = \frac{1 + 12\, d}{1 + 2\, d}$ .

Both $(1 + 2\, d)$ and $\left(\displaystyle \frac{1 + 12\, d}{1 + 2\, d}\right)$ are expressions for $r$ , the common ratio of this geometric sequence. Hence, equate these two expressions and solve for $d$ , the common difference of this arithmetic sequence.

$\displaystyle 1 + 2\, d = \frac{1 + 12\, d}{1 + 2\, d}$ .

$(1 + 2\, d)^{2} = 1 + 12\, d$ .

$d = 2$ .

Hence, the first term, the third term, and the thirteenth term of the arithmetic sequence would be $1$ , $(1 + (3 - 1) \times 2) = 5$ , and $(1 + (13 - 1) \times 2) = 25$ , respectively.

These three terms ( $1$ , $5$ , and $25$ , respectively) would correspond to the first three terms of the geometric sequence. Hence, the common ratio of this geometric sequence would be $r = 25 /5 = 5$ .

Let $a_1$ and $r$ denote the first term and the common ratio of a geometric sequence. The sum of the first $n$ terms would be:

$\displaystyle \frac{a_1 \, \left(1 - r^{n}\right)}{1 - r}$ .

For the geometric sequence in this question, $a_1 = 1$ and $r = 25 / 5 = 5$ .

Hence, the sum of the first $n = 7$ terms of this geometric sequence would be:

$\begin{aligned} & \frac{a_1 \, \left(1 - r^{n}\right)}{1 - r}\\ &= \frac{1 \times \left(1 - 2^{7}\right)}{1 - 2} \\ &= \frac{(1 - 128)}{(-1)} = 127 \end{aligned}$ .