If y is 5 when x is 2.5 and y varies directly with x, find y when x is 10

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stanley7 stanley7 · Answer 1 · 2019-06-19T13:50:24+02:00

Answer:

If x varies directly as y, then x=ky. y=5 and x=2.5 are substituted into x=ky to find k.

2.5=5k

k=2.5/5

k=5.

K =5 is substituted in x=ky to find y where x is 10.

x=5y

10=5y

y=10/2

y=2

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ColinJacobus ColinJacobus · Answer 2 · 2019-09-30T17:34:34+02:00

Answer: The required value of y is 20.

Step-by-step explanation: Given that y is 5 when x is 2.5 and y varies directly with x.

We are to find the value of y when x is 10.

According to the given information, we can write

[tex]y\propto x\\\\\Rightarrow y=kx~~~~~~~~~~[\textup{where k is the constant of proportionality}][/tex]

When y = 5 and x = 2.5, then we have

[tex]5=k\times2.5\\\\\Rightarrow k=\dfrac{5}{2.5}\\\\\Rightarrow k=2.[/tex]

So, we get

[tex]y=2x.[/tex]

Therefore, when x = 10, then the value of y is

[tex]y=2\times10=20.[/tex]

Thus, the required value of y is 20.