Question

the ratio of rock music to total CDs that Ella own is 25/40 polo has 50 rock music CDs the ratio of rock music to total CDs in his collection is equivalent to the ratio of rock music to total CDs in Ellas collectionHow many CDs do they own?

Answer 1

If Polo has $n$ CDs, then $\frac{50}n=\frac{25}{40}$ hence $n=\frac{50\cdot40}{25}=80$

Hence, they have a total of $80+40=\boxed{120\text{ CDs}}$