Answer:
Giselle worked as a carpenter for 12 hours and as a blacksmith for 18 hours last week
Explanation:
Let's assume that Giselle worked as a carpenter for x hours and as a blacksmith for y hours last week.
We know that she earns $20 per hour as a carpenter and $25 per hour as a blacksmith, and that she worked a total of 30 hours, so we can write two equations based on this information:
x + y = 30 (total hours worked)
20x + 25y = 690 (total earnings)
To solve for x and y, we can use substitution or elimination. Let's use substitution.
From the first equation, we can solve for x in terms of y:
x = 30 - y
Substitute this expression for x in the second equation:
20(30 - y) + 25y = 690
Simplify and solve for y:
600 - 20y + 25y = 690
5y = 90
y = 18
So Giselle worked as a blacksmith for 18 hours last week.
To find how long she worked as a carpenter, we can substitute y = 18 into the first equation and solve for x:
x + 18 = 30
x = 12
Therefore, Giselle worked as a carpenter for 12 hours last week.