Answer :

To determine which equation has a constant of proportionality equal to 2, let's examine each option:

1. Equation (A):
[tex]\[ y = \frac{10}{5} x \][/tex]
Simplify the fraction:
[tex]\[ \frac{10}{5} = 2 \][/tex]
Thus, equation (A) becomes:
[tex]\[ y = 2x \][/tex]
Here, the constant of proportionality is 2.

2. Equation (B):
[tex]\[ y = \frac{2}{2} x \][/tex]
Simplify the fraction:
[tex]\[ \frac{2}{2} = 1 \][/tex]
Thus, equation (B) becomes:
[tex]\[ y = 1x = x \][/tex]
Here, the constant of proportionality is 1.

3. Equation (C):
[tex]\[ y = \frac{2}{4} x \][/tex]
Simplify the fraction:
[tex]\[ \frac{2}{4} = \frac{1}{2} \][/tex]
Thus, equation (C) becomes:
[tex]\[ y = \frac{1}{2}x \][/tex]
Here, the constant of proportionality is [tex]\( \frac{1}{2} \)[/tex].

4. Equation (D):
[tex]\[ y = \frac{22}{2} x \][/tex]
Simplify the fraction:
[tex]\[ \frac{22}{2} = 11 \][/tex]
Thus, equation (D) becomes:
[tex]\[ y = 11x \][/tex]
Here, the constant of proportionality is 11.

From the above analysis, we can clearly see that only equation (A):
[tex]\[ y = \frac{10}{5} x \implies y = 2x \][/tex]
has a constant of proportionality equal to 2.

Therefore, the correct answer is:

(A) [tex]\( y = \frac{10}{5} x \)[/tex]