1. **State the problem:** Solve the system of equations for the cost of a bow and an arrow given: - The total cost of a bow and an arrow is 28. - The bow costs 21 more than the arrow. 2. **Write the equations:** Let $b$ be the cost of the bow and $a$ be the cost of the arrow. - Equation 1 (total cost): $$b + a = 28$$ - Equation 2 (difference in cost): $$b = a + 21$$ 3. **Substitute Equation 2 into Equation 1:** $$a + 21 + a = 28$$ 4. **Simplify and solve for $a$:** $$2a + 21 = 28$$ $$2a = 28 - 21$$ $$2a = 7$$ $$a = \frac{7}{2}$$ 5. **Calculate $b$ using Equation 2:** $$b = a + 21 = \frac{7}{2} + 21 = \frac{7}{2} + \frac{42}{2} = \frac{49}{2}$$ 6. **Final answer:** - Cost of the arrow: $a = 3.5$ - Cost of the bow: $b = 24.5$