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Nadusha1986 [10]
3 years ago
8

Let y=21 and x=1.5 if y varies directly with x find y when x=9

Mathematics
2 answers:
Svetllana [295]3 years ago
8 0
Y would be 42. if you multiple 1.5 by 3 it will be 9. so if divide 21 by 1.5 it equals 14 so multiple 14 by 3 it gives you 42
AnnZ [28]3 years ago
7 0
If y varies directly with x then we have the following function:
y=x + (21 - 1.5) or simply y = x + 19.5.
So, when x=9:
y = 9 + 19.5 = 28.5

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What is the sum of this geometric series?24 + 36 + ... + 121.5
krok68 [10]
The sum of the geometric series is 195
4 0
3 years ago
A county's population in 1991 was 147 million. In 1998 it was 153 million. Estimate the population in 2017 using the exponential
aliina [53]
Let t=number of years since 1991.
Then 
P(t)=147 e^(kt)   ... in millions
P(0)=147 e^(0)=147
P(7)=147 e^(7k)=153
e^(7k)=(153/147)
take ln both sides
ln(e^(7k))=ln(153/147)
7k=0.0400 => k=0.005715

Year 2017=>t=2017-1991=26
P(26)=147e^(26*.005715)=170.55
Answer: in 2017, the projected population is 170.55 millions.
6 0
3 years ago
A fruit bowl contains 2 bananas, 5 oranges, and 4 apples in the simplest form, what is the ratio of apples to bananas in the fru
prisoha [69]

Answer:

Ratio of apple to banana is 2:1

Step-by-step explanation:

To find ratio of x type of one thing and y type of other thing we divide

x by y and ratio is written as

ratio = x:y

_________________________________

Number  of banana = 2

Number  of apples = 4

Ratio of apple to banana = Number  of apples :Number  of banana

Ratio of apple to banana = 4:2

since 4 is divisible by 2 , to get the ratio in simplest form

we divide both numerator and denominator by 2

Ratio of apple to banana = 4/2:2 /2 = 2:1

Thus,

Ratio of apple to banana is 2:1

3 0
3 years ago
A neighborhood child is selling lemonade and cookies in front of his house. He has up to 20 cookies available and enough lemonad
prohojiy [21]

Answer:

The child can sell 15 cookies and 30 lemonade glasses, or 10 cookies and 40 glasses of lemonade, etc

Step-by-step explanation:

If the child wants to make $30 and gets $1 per cookie and $0.50 per lemonade glass, he could sell 15 cookies and 30 glasses, 10 cookies and 40 glasses, etc. He has to sell at least 5 cookies, though, as the lemonade is only worth $25.

7 0
3 years ago
It is given that y varies inversely as x^2. If x is decreased by 50%, find the percentage change in y.
vova2212 [387]

Answer:

300%

Step-by-step explanation:

Given

y\ \alpha\ \frac{1}{x^2}

Required

Find the percentage change in y when x decreased by 50%

First, convert to equation

y\ = \ \frac{k}{x^2}

Where k is the constant of proportionality

When x decreased by 50%

Y = \frac{k}{(x - 0.5x)^2}

Y = \frac{k}{(0.5x)^2}

Y = \frac{k}{0.25x^2}

Expand

Y = \frac{1}{0.25} * \frac{k}{x^2}

Substitute \frac{k}{x^2} for y

Y = \frac{1}{0.25} * y

Y = 4 * y

Y = 4 y

The percentage change is then calculated as:

\%Change = \frac{Y - y}{y} * 100\%

\%Change = \frac{4y - y}{y} * 100\%

\%Change = \frac{3y}{y} * 100\%

\%Change = 3 * 100\%

\%Change = 300\%

<em>The percentage in y is 300%</em>

7 0
3 years ago
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