p = c + 2.25, so p + c = 2c + 2.25

e = 23.75 – 2c – 2.25 = 21.5 – 2c, so

689.25 = 25(21.5 – 2c) + 27c + 33(c + 2.25), and

689.25 = 537.5 – 50c + 27c + 33c + 74.25, or 10c + 611.75.

Then 10c = 77.5, and c = 7.75, and e = 6

25e + 27c + 33p = 689.25

p = 2.25 + c so…

25e + 27c + 33(2.25+c) = 689.25

25e + 27c + 74.25 +33c = 689.25

25e + 60c = 615

23.75 = e + c + p

23.75 = e + c + 2.25 + c

21.50 = e + 2c

e = 21.50 – 2c

so…back to the previous one…

25e + 60c = 615

25 (21.50-2c) + 60c = 615

537.5 – 50 c + 60 c = 615

10c = 77.5

c = 7.75

so…

e = 21.50-2c

e = 21.50 – (2*7.75)

e = 21.5 – 15.5

e = 6

so, the electrician works for 6 hours.

the hours each one worked,will be a,b,and c.

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a+b+c=23.75hours. (1)

25a+27b+33c=689.25$ (2)

c=b+2.25 (3)

now,u will put (3)into (1):

a+b+b+2.25=23.75

a+2b=21.5 ==>a=21.5-2b (4)

now you will put (4) & (3) into (1) and you will find b.

then go to (4),plug in the result that you’ve found for b and you will have a…..