I converted 13% to 0.13 but I do not know how to solve this problem.
15% of the total = 35 (by the way "of" almost always means multiply)
let t be the total
So,
.15 t = 35
divide by .15 to get t by itself
So,
35/.15 = 233.33333
Thus the total number of seals is about 233.
Bill