A knight (from a fairy tale) paid 25 gold coins for a spear, a shield, a sword, and a horse.
A shield, a sword, and a horse cost 22 gold coins altogether.
A spear, a shield and a sword cost 15 gold coins altogether.
A spear, a shield , and a horse cost 17 gold coins altogether.

How much did the knight pay for each of these items:
Q1: a spear,
Q2: a shield,
Q3: a sword?