Question 833831
3*10=30 hours
5*10=50 hours
x/3+x/5=1 They would do the job in 18/7 (x = 1.875) days together.
x/30+x/50=1  They would do the job in 75/4 (x = 18.75) hours together.

but Maria is only working 4 hours a day or 4/10 of the time
(4/10)x/30+x/50=1 

x=30 it will take them 30 hours together if Maria works 4 hours a day