Ask question

Ask question

All categories

kakasveta [241]

3 years ago

11

In 1990 retail sales at bookstores were about $7.4 billion. In 1997 retail sales at bookstores were about $11.8 billion. Write a

linear model for retail sales s (in billions of dollars) at bookstores from 1990 through 1997. Let T represent the number of year since 1990. Then estimate the retail sales at bookstores in 2012.

1 answer:

love history [14]3 years ago

8 0

hopefully this helps you and gives you insight in how to solve the problems from now on (:

= $11.8 + (2012-1997)([$11.8-$7.4][1997-1990])

= $11.8 + 5 ($4.4/7)

= $11.8 4/5 + $22/7

= $59/5 + $22/7

= $413/35 + $110/35

= $523/35 or $14 33/35

answer : SALES IN 2012 WOULD BE $14 33/35 BILLION OR $14.9 3/7

You might be interested in

Please help i give brainlist

Anastasy [175]

Hello There!

The ratio is 1:3 therefore the answer is 1/3

Hope This Helps You!
Good Luck :)

- Hannah ❤

3 0

3 years ago

Read 2 more answers

Find the surface area of a 7.4 cm long iron rod and 3.1 m radius

Debora [2.8K]

Answer:

144.2 cm

Step-by-step explanation:

Length of the iron rod is 7.4cm

Radius is 3.1m

Therefore the surface area can be calculated as follows

= 2πrl

= 2×3.142×3.1×7.4

= 144.2 I'm

Hence the surface area is 144.2cm

3 0

3 years ago

Write out the first four terms of the series to show how the series starts. Then find the sum of the series or show that it dive

Nostrana [21]

Answer:

The first four terms of the series are

$(9+3),(\frac97+\frac35),(\frac9{7^2}+\frac3{5^2}),(\frac9{7^3}+\frac3{5^3})$

$\sum_{n=0}^\infty \frac9{7^n}+\frac{3}{5^n}$ = 14.25

Step-by-step explanation:

We know that

Sum of convergent series is also a convergent series.

We know that,

$\sum_{k=0}^\infty a(r)^k$

If the common ratio of a sequence |r| <1 then it is a convergent series.

The sum of the series is $\sum_{k=0}^\infty a(r)^k=\frac{a}{1-r}$

Given series,

$\sum_{n=0}^\infty \frac9{7^n}+\frac{3}{5^n}$

$=(9+3)+(\frac97+\frac35)+(\frac9{7^2}+\frac3{5^2})+(\frac9{7^3}+\frac3{5^3})+.......$

The first four terms of the series are

$(9+3),(\frac97+\frac35),(\frac9{7^2}+\frac3{5^2}),(\frac9{7^3}+\frac3{5^3})$

Let

$S_n=\sum_{n=0}^\infty \frac{9}{7^n}$ and $t_n=\sum_{n=0}^\infty \frac{3}{5^n}$

Now for $S_n$ ,

$S_n=9+\frac97+\frac{9}{7^2}+\frac9{7^3}+.......$

$=\sum_{n=0}^\infty9(\frac 17)^n$

It is a geometric series.

The common ratio of $S_n$ is $\frac17$

The sum of the series

$S_n=\sum_{n=0}^\infty \frac{9}{7^n}$

$=\frac{9}{1-\frac17}$

$=\frac{9}{\frac67}$

$=\frac{9\times 7}{6}$

=10.5

Now for $t_n$

$t_n= 3+\frac35+\frac{3}{5^2}+\frac3{5^3}+.......$

$=\sum_{n=0}^\infty3(\frac 15)^n$

It is a geometric series.

The common ratio of $t_n$ is $\frac15$

The sum of the series

$t_n=\sum_{n=0}^\infty \frac{3}{5^n}$

$=\frac{3}{1-\frac15}$

$=\frac{3}{\frac45}$

$=\frac{3\times 5}{4}$

=3.75

The sum of the series is $\sum_{n=0}^\infty \frac9{7^n}+\frac{3}{5^n}$

= $S_n+t_n$

=10.5+3.75

=14.25

4 0

3 years ago

You rode a bicyde for 2 hours and travelled 43 km, calculate your average<br>speed.

cupoosta [38]

Answer:

22.5km per hour

Step-by-step explanation:

5 0

3 years ago

Write an equation of the ellipse with foci at (+3,0) and co-vertices at (0, +-1).

trapecia [35]

Good luck hope this helps

5 0

3 years ago