how many hours did penny work in each job

Question

Penny has two jobs during the day she works as an office clerk in in the evening she works as a tutor her office job pays her $18 per hour her tutoring job pays 1575 per hour in one week penny worked 42 hours she earned a total of 738 how many hours the penny work in each job

Answer 1

Let C=clerk hours and T=tutor hours.

So C+T=42, T=42-C

18C+15.75T=738.

18C+15.75(42-C)=738

18C+661.50-15.75C=738

2.25C=738-661.50=76.50

C=76.50/2.25=34 hr and so T=42-34=8 hr.

She works 34 hours as a clerk and 8 hours as a tutor.