Total sales= 138 440$
For the level 1 we know that we have 1% on the first 50000 of sales so we can do this:
50000* 0.01= 500$
Now the remaining amount would be:
138440- 50000= 88440$
Now we can calculate the next level with this:
75000* 0.015= 112.5$
And then we have remaining 88440- 75000= 13440$
And the commission for Level 3 would be:
13440 * 0.02 = 268.8$
And the total commission would be:
500 + 112.5 + 268.8 $= 881.3$