ANSWER QUICK PLEASE

A mobile company charges a fixed rate of x cents per minute for the first 120 minutes of talk time and another rate of y cents p

patriot [66]

Answer:

$21.2

Step-by-step explanation:

From the problem given, we express them as algebra so that we can easily solve;

the total charge on a call greater than 120min is given as;

120x + y(n - 120) = total cost of call

where n is the number of minutes which is greater than 120;

Ethan paid $26.80 for 175 mins

n = 175min here;

120x + y(175 - 120) = 26.80

120x + 55y = 26.80 ----- (I)

$32.40 for 210 minutes

n = 210min

120x + y(210 - 120) = 32.4

120x + 90y = 32.4 ----- (II)

Now let us solve both equations for y and x;

120x + 55y = 26.80 ----- (I)

120x + 90y = 32.4 ----- (II)

subtract the two equations;

90y - 55y = 32.4 - 26.8

35y = 5.6

y = $\frac{5.6}{35}$ = 0.16cents

then x;

120x = 26.8 - 55y from equation I

120x = 26.8 - 55(0.16)

120x = 18

x = $\frac{18}{120}$ = 0.15cents

Find the cost of 140min of talk time;

n =140min;

= 120(0.15) + 0.16(140 - 120)

= 18 + 0.16(20)

= 18 + 3.2

= $21.2

4 0

3 years ago

7m2 + 3m + 4m2<br> What is the answer to this

mylen [45]

I’m assuming the 2’s are supposed to be exponents so you’re gonna to combine 7m^2 and 4m^2 to get 11m^2 so you’re answer would be

11m2+3m

You dint know the value of M so you can’t solve it, especially because there’s no equal sign with a number or expression/equation after it.

8 0

3 years ago

A ladder 16 feet long is leaning against the wall of a tall building. The base of the ladder is moving away from the wall at a r

svet-max [94.6K]

Answer:

a. 0.588

b. 0.0722

c. 4.576 sqft/sec

Step-by-step explanation:

Let b and h denote the base and height as indicated in the diagram. By pythagoras theorem, $h^2 + b^2 = 16^2 = 256 \dotsc\;(1)$ because it is a right angle triangle.

It is given that $\frac{db}{dt} = 1$

Now differentiate (1) with respect to t (time) :

$\displaystyle{2h\frac{dh}{dt} + 2b\frac{db}{dt} = 0 \implies \frac{dh}{dt} = -\frac{b}{h} \frac{db}{dt}}$

$\displaystyle{=-\frac{b}{\sqrt{256 - b^2}} \frac{db}{dt} = -\frac{8}{13.856} \times 1 = -0.588}$

The minus sign indicates that the value of h is actually decreasing. The required answer is 0.588.

b. From the diagram, infer that $16 \sin{\theta} = b$ . When b = 8, then $\theta = \arcsin{0.5} = \ang{30}$ .

Differentiate the above equation w.r.t t

$\displaystyle{16 \cos{\theta} \frac{d\theta}{dt} = \frac{db}{dt} \implies \frac{d\theta}{dt} = \frac{1}{16 \cos{\theta}} = \frac{1}{13.856} = \mathbf{0.0722}}$