Ask question

Ask question

All categories

3 years ago

7

a cell phone store sells the basic model of a phone for $30 and the upgraded model for $100 when a customer signs a two-year agr

eement. on tuesday, the store has $900 in sales. the store pays $5 for each basic model and $25 for each upgraded model. if the cost of the cell phones sold on tuesday is $200, how many upgraded models were sold?

2 answers:

alisha [4.7K]3 years ago

8 0

30b + 100u = 900
5b + 25u = 200....multiply by -6
------------------
30b + 100u = 900
-30b - 150u = - 1200 (result of multiplying by -6)
------------------add
-50u = - 300
u = 6 <== upgrated phones sold

30b + 100u = 900
30b + 100(6) = 900
30b + 600 = 900
30b = 900 - 600
30b = 300
b = 10 <== basic phones sold

JulijaS [17]3 years ago

7 0

Answer:

10

Step-by-step explanation:

You might be interested in

In a random sample of 400 residents of Boston, 320 residents indicated that they voted for Obama in the last presidential electi

coldgirl [10]

Answer:

C.I = 0.7608 ≤ p ≤ 0.8392

Step-by-step explanation:

Given that:

Let consider a random sample n = 400 candidates where 320 residents indicated that they voted for Obama

probability $\hat p = \dfrac{320}{400}$

= 0.8

Level of significance ∝ = 100 -95%

= 5%

= 0.05

The objective is to develop a 95% confidence interval estimate for the proportion of all Boston residents who voted for Obama.

The confidence internal can be computed as:

$=\hat p \pm Z_{\alpha/2} \sqrt{\dfrac{ p(1-p)}{n } }$

where;

$Z_{0.05/2}$ = $Z_{0.025}$ = 1.960

SO;

$=0.8 \pm 1.960 \sqrt{\dfrac{ 0.8(1-0.8)}{400 } }$

$=0.8 \pm 1.960 \sqrt{\dfrac{ 0.8(0.2)}{400 } }$

$=0.8 \pm 1.960 \sqrt{\dfrac{ 0.16}{400 } }$

$=0.8 \pm 1.960 \sqrt{4 \times 10^{-4}}$

$=0.8 \pm 1.960 \times 0.02}$

$=0.8 \pm 0.0392$

= 0.8 - 0.0392 OR 0.8 + 0.0392

= 0.7608 OR 0.8392

Thus; C.I = 0.7608 ≤ p ≤ 0.8392

3 0

3 years ago

Begin by translating polygon ABCD. Create a line segment of length 5 units to the right of points A, B, C, and D. Connect the po

valentina_108 [34]

Answer: As GH moves, the reflected image changes its position with respect to the position of the line. The polygons will touch one another if the line of reflection touches polygon ABCD.

5 0

3 years ago

Read 2 more answers

Find B on AC that is 2/5 of the distance of A to C.

salantis [7]

Answer:

1

Step-by-step explanation:

AC = 5, ao AB = 2.

This means B = -1+2 = 1.

3 0

2 years ago

Which name does not apply to the figure? A. quadrilateral B. square C. parallelogram D. rhombus

aivan3 [116]

The answer is B.
-Corey

8 0

3 years ago

Read 2 more answers

A pyramid has a square base of length 8cm and a total surface area of 144cm². Find the volume of the pyramid. (Please use Pythag

Sveta_85 [38]

Answer:

$\displaystyle V_{ \text{pyramid}}= 64 \: {cm}^{3}$

Step-by-step explanation:

we are given surface area and the length of the square base

we want to figure out the Volume

to do so

we need to figure out slant length first

recall the formula of surface area

$\displaystyle A_{\text{surface}}=B+\dfrac{1}{2}\times P \times s$

where B stands for Base area

and P for Base Parimeter

so

$\sf\displaystyle \: 144=(8 \times 8)+\dfrac{1}{2}\times (8 \times 4) \times s$

now we need our algebraic skills to figure out s

simplify parentheses:

$\sf\displaystyle \: 64+\dfrac{1}{2}\times32\times s = 144$

reduce fraction:

$\sf\displaystyle \: 64+\dfrac{1}{ \cancel{ \: 2}}\times \cancel{32} \: ^{16} \times s = 144 \\ 64 + 16 \times s = 144$

simplify multiplication:

$\displaystyle \: 16s + 64 = 144$

cancel 64 from both sides;

$\displaystyle \: 16s = 80$

divide both sides by 16:

$\displaystyle \: \therefore \: s = 5$

now we'll use Pythagoras theorem to figure out height

according to the theorem

$\displaystyle \: {h}^{2} + (\frac{l}{2} {)}^{2} = {s}^{2}$

substitute the value of l and s:

$\displaystyle \: {h}^{2} + (\frac{8}{2} {)}^{2} = {5}^{2}$

simplify parentheses:

$\displaystyle \: {h}^{2} + (4 {)}^{2} = {5}^{2}$

simplify squares:

$\displaystyle \: {h}^{2} + 16 = 25$

cancel 16 from both sides:

$\displaystyle \: {h}^{2} = 9$

square root both sides:

$\displaystyle \: \therefore \: {h}^{} = 3$

recall the formula of a square pyramid

$\displaystyle V_{pyramid}=\dfrac{1}{3}\times A\times h$

where A stands for Base area (l²)

substitute the value of h and l:

$\sf\displaystyle V_{ \text{pyramid}}=\dfrac{1}{3}\times \{8 \times 8 \}\times 3$

simplify multiplication:

$\sf\displaystyle V_{ \text{pyramid}}=\dfrac{1}{3}\times 64\times 3$

reduce fraction:

$\sf\displaystyle V_{ \text{pyramid}}=\dfrac{1}{ \cancel{ 3 \: }}\times 64\times \cancel{ \: 3}$

hence,

$\sf\displaystyle V_{ \text{pyramid}}= 64 \: {cm}^{3}$

8 0

3 years ago