Let x hours be the number of hours Issac worked
x+6 hours be the number of hours Ruby worked
4(x+6) hours be the number of hours Svetlana worked.
x + x + 6 + 4(x+6) = 126
x + x + 6 + 4x +24 = 126
6x +30 = 126
6x = 96
x = 16
Therefore, Issac worked 16 hours.
Ruby worked 16+6 = 22 hours
Svetlana worked 22 × 4 = 88 hours.