R + R - 6 + 4R = 126
6R - 6 = 126
6R = 126 + 6
6R = 132
R = 132/6
R = 22 (hours Ruby worked)
I = R - 6
I = 22 - 6
I = 16 (hours Isaac worked)
S = 4R
S = 4(22)
S = 88 (hours Svetlana worked)
Finally, let's check our three answers to see if their sum is 126 (the given total of hours worked):
22 + 16 + 88 = 38 + 88 = 126