Two mechanics worked on a car. the first mechanic charged $65 per hour, and the second mechanic charged $105 per hour. the mechanics worked for a combined total of 35 hours, and together they charged a total of $2875 . how long did each mechanic work?

X=number of hours mechanic one worked
y=number of hours of mechanic 2

so

65x+105y=2875 and
x+y=35
solve, use elimination
multiply 2nd equation by -65 and add to first one

-65x-65y=-2275
65x+105y=2875 +
0x+40y=600

40y=600
divide by 40 boht sides
y=15

sub back
x+y=35
x+15=35
x=20

the first one worked 20 hours
2nd one worked 15 hours

The expressions would be 0.25a