If a pendulum$-$driven clock gains $7\frac{s}{?}$ day, what fractional change in pendulum length must be made for it to keep perfect time? Express your answer as a percentage change; keep sufficient significant figures.

Note: this problem may seem a little intimidating, but you can do it$!$ Read both of the hints carefully, and think about what quantities are changing and which are not.

$\frac{dl}{l}=$