The ratio of the pocket money saved by Lokesh and his sister is 5 : 6. If the sister saves ₹ 30 more, how much more the brother should save in order to keep the ratio of their savings unchanged.

Let the savings of Lokesh and his sister are 5x and 6x.

Let Lokesh save ₹ y more then according to question,

$\Rightarrow \dfrac{5x + y}{6x + 30} = \dfrac{5}{6} \\[0.5em] \Rightarrow 6(5x + y) = 5(6x + 30) \\[0.5em] \Rightarrow 30x + 6y = 30x + 150 \\[0.5em] \Rightarrow 6y = 150 \\[0.5em] \Rightarrow y = 25.$

Hence, Lokesh should save ₹ 25 more.