This question was not properly written, hence it is incomplete. The complete question is written below:
Complete Question:
Abigail and Liza work as carpenters for different companies. Abigail earns $20 per hour at her company and Liza earns $25 per hour at her company. Last week, Abigail and Liza worked for a total of 30 hours and together earned a total of $690. How many hours did Liza work last week?
Answer:
Lisa worked for 18 hours last week
Explanation:
Let the number of hours Abigail worked last week = A
Let the number of hours Liza worked last week = B
Abigail earns = $20 per hour at her company
Liza earns = $25 per hour at her company
A + B = 30 ........... Equation 1
B = 30 - A
20 × A + 25 × B = 690
20A + 25B = 690 ............... Equation 2
Substitute 30 - A for B in Equation 2
Hence, we have:
20A + 25(30 - A) = 690
20A + 750 - 25A = 690
Collect like terms
20A - 25A = 690 - 750
-5A = -60
A = -60/-5
A = 12
Since A represents the number of hours Abigail worked, Abigail worked for 12 hours last week.
Substitute 12 for A in Equation 1
A + B = 30
12 + B = 30
B = 30 - 12
B = 18
Since B represents the number of hours Liza worked, therefore, Liza worked for 18 hours last week.