According to question, r1 = k[X]2 …(i)
If concentration is increased to three times, then
r2 = k [3X]2
r2 = k 9 X2
r2 = 9k [X]2 …(ii)
Divide eq (ii) by eq. (i)
\({ r_{ 2 } }{ r_{ 1 } } =\frac { 9k[X]^{ 2 } }{ k[X]^{ 2 } } \)
\(\frac { r_{ 2 } }{ r_{ 1 } } =9 \)
r2 = 9 x rı
i.e., if concentration is increased there times, the rate increases 9 times.