Respuesta :
Answer: She worked 12 hours as a carpenter and 18 hours as a blacksmith last week.
Step-by-step explanation:
Let x be the number of hours for which she worked as a carpenter and y be the number of hours for which she worked as a blacksmith,
Since, total numbers of hours she worked = 30,
⇒ x + y = 30 ------(1)
Also, she earned total $ 690 in which she earned $20 dollar per hour as a carpenter and $25 per hour as a blacksmith.
⇒ 20 x + 25 y = 690 ------(2)
Equation (2) - 20 × Equation (1),
We get,
5 y = 90 ⇒ y = 18
After substituting this value in equation (1),
We get, x = 12,
Hence, She worked as a carpenter = x hours = 12 hours
And, as a blacksmith = y hours = 18 hours
