Question

Y varies directly as x . If y = 20 when x = 4 .find the constant of proportionality?

Answer 1

SOLUTION

GIVEN

y varies directly as x .

y = 20 when x = 4

TO DETERMINE

The constant of proportionality

EVALUATION

Here it is given that y varies directly as x

Then

$\sf{y \propto \: x}$

∴ y = kx - - - - (1)

where k = constant of proportionality

Now it is given that y = 20 when x = 4

Thus from equation 1 we get

20 = 4k

∴ k = 5

∴ The constant of proportionality = 5

FINAL ANSWER

The constant of proportionality = 5

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Answer 2

Step-by-step explanation:

Here it is given that y varies directly as x

Then

\sf{y \propto \: x}y∝x

∴ y = kx - - - - (1)

where k = constant of proportionality

Now it is given that y = 20 when x = 4

Thus from equation 1 we get

20 = 4k

∴ k = 5