Initial charge charged by the Singer A = $50
Hourly charge of Singer A = $20
Initial amount charged by Singer B = $100
Hourly rate charged by Singer B = $10
Let us assume the time after which both singers will charge the smae amount of money = x
Then
50 + 20x = 100 + 10x
20x -10x = 100 - 50
10x = 50
x = 50/10
= 5
So after 5 hours both Singer A and Singer B will charge the same amount of money. I hope the procedure is clear to you and you can attempt such problems in future without needing any kind of help.
