The value of x when y = 25 is 10.
Thus, the correct answer to the question is Option A. 10
From the question given above, we were told that y varies directly as x. This can be written as:
y ∝ x
Removing the proportionality sign, we have
Next, we shall determine the constant K. This can be obtained as follow:
x = 4
y = 10
y = Kx.
10 = K × 4
Divide both side by 4
[tex]K = \frac{10}{4} \\\\K = \frac{5}{2}[/tex]
Finally, we shall determine x when y is 25.
[tex]K = \frac{5}{2}[/tex]
y = 25
y = Kx
[tex]25 = \frac{5}{2}x[/tex]
Cross multiply
5x = 25 × 2
5x = 50
Divide both side by 5
[tex]x = \frac{50}{5} \\\\[/tex]
The value of x when y = 25 is 10.
Therefore, the correct answer to the question is Option A. 10
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