Answer:
Carpenter 12 hours and 18 hours blacksmith
Explanation:
Let x = carpenter
Let y = hours working as a blacksmith
x + y = 30 ⇒ x -20 ⇒ -20x -20y = -600
20x + 25 y = 690 ⇒ 20x + 25y = 690
5y = 90 Divide both sides by 5
y = 18
Giselle worked 18 hours as a blacksmith.
x + y = 30
x + 18 = 30 Subtract 18 from both sides
x + 18 - 18 = 30 - 18
x = 12
Giselle worked 12 hours as a carpenter.
Helping in Jesus' name.