We aer goint to eliminate the x's
multiply first by -5 and 2nd by 2
so that is B
1. 0 - 34 + 13 - 5 = -26.....26 ft below the surface
2. y = 15x + 50
220 = 15x + 50
220 - 50 = 15x
170 = 15x
170/15 = x
11 1/3 = x......he worked 11 1/3 hrs.......not sure about this...because it does not specify how many visits he made...but if this was just for 1 visit, then he worked 11 1/3 hrs
The correct answer here would be the third choice or NK
hope this helps