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2 years ago

If the ratio of y to x is equal to 3 and the sum of y and x is 80, what is value of y

Mathematics

1 answer:

Rus_ich [418]2 years ago

3 0

Answer:

y = 60

Step-by-step explanation:

<h3>Step 1: Make sense of the given</h3>

"The ratio of y to x is 3"

This means that, $y\div x=3$

"The sum of y and x is 80"

This means, $x+y=80$

<h3>Step 2: Make use of the facts</h3>

If $y\div x=3$ , then $y = (3*x)$ .

We can plug this into the other equation by substitution:

$x + (3 * x)=80$

This simplifies to:

$4x = 80$

Which we can solve out and get:
$x=20$ .

We solved for x, but we need the value of y.

So, we go back to the equation we first derived: " $y = (3*x)$ ".

And now we substitute the value of x, into this.

$y = (3 * (20))$

By solving this out, we get:
$y=60$

So, the value of y is 60.

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A basketball shot is taken from a horizontal distance of 5m from the hoop. The height of the ball can be modelled by the relatio

olasank [31]

This is the concept of application of quadratic expressions. Given that the height of the ball is modeled by the equation;
h=-7.3t^2+8.25t+2.1+5
The time taken for the ball to hit the ground will be given as falls;
-7.3t^2+8.25t+7.1=0
to solve for t we use the quadratic formula;
t=[-b+/-sqrt(b^2-4ac)]/(2a)
a=-7.3, b=8.25, c=2.1
t=[-8.25+/-sqrt[8.25^2+4*7.3*7.1]/(-2*7.3)
t= -0.572
or
t=1.702
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7 0

3 years ago

A new phone costs $230 and the sales tax rate is 7%. What is the total cost of the camera after tax?

rosijanka [135]

That's a question about percentage.

One way to represent percentage is using decimal number. In this way, 1 is equivalent to 100% and the other less percentages using numbers between 0 and 1.

Examples:

90% is equivalent to 0,90.
5% is equivalent to 0.05. It's not 0.5 because 0.5 is equivalent to 50%.
13.17% is equivalent to 0.1317.
245% is equivalent to 2.45.

If we want to know the percentage of a number, we should multiplacate the number by the porcentage in the decimal number form.

Examples:

55.90% of 200 is equal to: $200 \times 0.5590 = 111.8$

360% of 88 is equal to: $88\times 3.6 = 316.8$

In our problem, we have a phone with a increase of 7%. To solve that, it's important to perceive that $230 is equal to 100% and with a increase of 7%, we will pay 107%.

107% in the decimal number form is 1.07. With that information, we should multiplicate 1.07 by the original value and we will find the answer.

We know that $230\times 1.07 = 246.1$ , therefore, the total cost of the phone after tax is $246.1.