two mechanics worked on a car the first mechanic charged 105 per hour and the second mechanic charged 80 per hour the mechanics worked for a combined total of 15 hours

Question

two mechanics worked on a car the first mechanic charged 105 per hour and the second mechanic charged 80 per hour the mechanics worked for a combined total of 15 hours and together they charged a total of 1450 how long did each mechanic work?

Answer 1

F+S=15

105F+80S = 1450

multiply the 1st equation by 80 and subtract from the 2nd to eliminate 1 variable

80F +80S = 1200

25F = 250

F = 10 hours for first mechanic

S = 5 hours for 2nd mechanic