Two mechanics worked on a car the first mechanic charge $55 per hour the second mechanic charge $80 per hour the mechanics work for a combined total of 15 hours and together they charged a total of $950 how long did the mechanic work?

a = hours worked by the first mechanic

b = hours worked by the second mechanic.

since the first mechanic charges $55 per hour, then for "a" hours that'd be a total of 55*a or 55a, likewise, for the second mechanic that'd be a total charge of 80*b or 80b.

we know all hours combined are 15, so then a + b = 15.

we also know that all charges combined are $950, so 55a + 80b = 950.