MATH SOLVE

5 months ago

Q:
# Giselle works as a carpenter and as a blacksmith. She earns $ 2 0 $20dollar sign, 20 per hour as a carpenter and $ 2 5 $25dollar sign, 25 per hour as a blacksmith. Last week, Giselle worked both jobs for a total of 3 0 3030 hours, and earned a total of $ 6 9 0 $690dollar sign, 690. How long did Giselle work as a carpenter last week, and how long did she work as a blacksmith?

Accepted Solution

A:

She worked as a carpenter for 12 hours and as a blacksmith for 18 hours.

Assuming you mean she earned $20 as a carpenter and $25 as a blacksmith per hour, with a total of 30 hours for $690,

let c represent carpenter hours and b for blacksmith hours.

20c + 25b = 690

c + b = 30

Subtract b from each side so that c = 30 - b

Plug this value into the first equation

20(30 - b) + 25b = 690

600 - 20b + 25b = 690

600 + 5b = 690

5b = 90

b = 18

To find c, plug this value of b into the other equation

c + 18 = 30

c = 12

Assuming you mean she earned $20 as a carpenter and $25 as a blacksmith per hour, with a total of 30 hours for $690,

let c represent carpenter hours and b for blacksmith hours.

20c + 25b = 690

c + b = 30

Subtract b from each side so that c = 30 - b

Plug this value into the first equation

20(30 - b) + 25b = 690

600 - 20b + 25b = 690

600 + 5b = 690

5b = 90

b = 18

To find c, plug this value of b into the other equation

c + 18 = 30

c = 12