work rate in hours for both 60(k+m)
total amount of work to be performed 500-200 = 300
then:
60(k+m) *x hours = 300
X hours = 300/60(k+m) = 5/(k+m)
total amount of work to be performed 500-200 = 300
then:
60(k+m) *x hours = 300
X hours = 300/60(k+m) = 5/(k+m)
