2/80 is equivalent
you can also just multiply the numerator and denominator to find out what else is equivalent.
Total cost=$142
cost of parts=$62
cost paid for labour=$142-$62=$80
According to question,
》cost of labour per hr=$32
which can be written as,
》cost of labour/time=$32
Use cross multiplication,
》time=cost of labour/32
Since cost of labour is 80,
Time=80/32
=2.5hrs
-----------------------------------------------------
