Q1: The white horse was first in the race. The brown horse was first too.
Both _________________
Both the white and the brown horses were first.
or
Both white and brown horses were first.
Q2: My mother is going to the bookshop. My father is going to the bookshop too.
Both __________________
Both my mother and my father are going to the bookshop.
or
Both my mother and father are going to the bookshop.
Q3: The watch is expensive. The clock is expensive too.
Both the watch and the clock are expensive.
or
Both watch and clock are expensive.