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3 years ago

80% of what number is 15?

1 answer:

3 0

15 = 80% * x

15 = 80/100 * x

15 = 8/10 * x

x = 15 * 10/8

x = 150/8

x = 18.75

<span>80% of 18.75 is </span>15<span>.</span>

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All the applicants chose at least one of the three countries Egypt, Ghana and South Africa. A total of 2417 applicants chose Egy

cestrela7 [59]

Answer:

hard quiz

Step-by-step explanation:

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3 years ago

A biologist has been observing a tree's height. This type of tree typically grows by 0.22 feet each month. Fifteen months into t

Lyrx [107]

Data:

x: number of months

y: tree's height

Tipical grow: 0.22

Fifteen months into the observation, the tree was 20.5 feet tall: x=15 y=20.5ft (15,20.5)

In this case the slope (m) or rate of change is the tipical grow.

m=0.22

To find the line's slope-intercep equation you use the slope (m) and the given values of x and y (15 , 20.5) in the next formula to find the y-intercept (b):

$\begin{gathered} y=mx+b \\ 20.5=0.22(15)+b \\ 20.5=3.3+b \\ 20.5-3.3=b \\ 17.2=b \end{gathered}$

Use the slope(m) and y-intercept (b) to write the equation:

$\begin{gathered} y=mx+b \\ \\ y=0.22x+17.2 \end{gathered}$ A) This line's slope-intercept equation is: y=0.22x+17.2

B) To find the height of the tree after 29 months you substitute in the equation the x for 29 and evaluate to find the y:

$\begin{gathered} y=0.22(29)+17.2 \\ y=6.38+17.2 \\ \\ y=23.58 \end{gathered}$ Then, after 29 months the tree would be 23.58 feet in height

C) In this case as you have the height and need to find the number of moths you substitute the y for 29.96feet and solve the equation for x, as follow:

$\begin{gathered} 29.96=0.22x+17.2 \\ 29.96-17.2=0.22x \\ 12.76=0.22x \\ \frac{12.76}{0.22}=x \\ \\ 58=x \end{gathered}$ Then, after 58 months the tree would be 29.96feet tall

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1 year ago

Rosita can wax her car in 2 hours or 120 minutes. When she works together with Helga, they can wax the car in 45 minutes. How lo

Mashcka [7]

<h2>Time taken by Helga to wax the car is 72 minutes</h2>

Step-by-step explanation:

Let w be the work of waxing.

Rosita can wax her car in 2 hours or 120 minutes.

Time taken by Rosita = 120 minutes

$\texttt{Rate of Rosita = }\frac{W}{120}$

Let time taken by Helga be t,

$\texttt{Rate of Helga = }\frac{W}{t}$

When she works together with Helga, they can wax the car in 45 minutes.

We have

$\frac{W}{\frac{W}{120}+\frac{W}{t}}=45\\\\120t=45(120+t)\\\\120t=5400+45t\\\\t=72minutes$

Time taken by Helga to wax the car is 72 minutes

6 0

3 years ago

Five pencils and 4 erasers cost $7.65. Four pencils and 5 erasers cost $7.20.What is the cost of 2 erasers?

Arturiano [62]

I think this is right.. I tried my best. If u get it sorry... I’m very sorry

1. Divide 7.20 by 4 since the 4 are the pencils

2.divide 7.20 by 5 ( 5 represents the erasers )

3. Then finally multiply 1.44 from 7.20/5 and
2 and u get 2.88

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3 years ago

A school system is reducing the amount of dumpster loads of trash removed each week. In week 5, there were 60 dumpster loads of

Lana71 [14]

Answer:

f(x) = -4x + 80

Step-by-step explanation:

You are given two points,

(5, 60) and (10, 40)

in order to get the equation, let's use the form slope-intercept form

m = (y1 - y2) / (x1 - x2)

m = (60 - 40) / (5 - 10)

m = 20/-5

m = -4

Get the x intercept

y = mx + b

60 = (-4)(5) + b

b = 60+20

b = 80

so the equation is

y = -4x + 80

f(x) = -4x + 80

5 0

2 years ago