Q:

Giselle works as a carpenter and as a blacksmith. She earns \$20$20dollar sign, 20 per hour as a carpenter and \$25$25dollar sign, 25 per hour as a blacksmith. Last week, Giselle worked both jobs for a total of 303030 hours, and earned a total of \$690$690dollar sign, 690. How long did Giselle work as a carpenter last week, and how long did she work as a blacksmith? Giselle worked as a carpenter for hours and as a blacksmith for hours last week.

Accepted Solution

A:
She earns 20 dollars as a carpenter and 25 dollars as a blacksmithb+c=30 hours since she works 30 hours a week25b+20c=690 since she earns 690 dollar totally and earns 25 dollars an hour as a blacksmith and 20 dollars an hour as a carpenterlets multiply b+c=30 by -20-20b-20c=-600if we substract that from 25b+20c=6905b=90b=18 she worked as a blacksmith for 18 hours