Answer:
$15
Step-by-step explanation:
let the hourly rate of pay for Ben  = B 
 let the hourly rate of pay for Judy  = J
Judy worked 4 hours and Ben worked 1 hour, their combined pay was $75; 
               4J + B = 75 ----- i 
 Judy worked 2 hours and Ben worked 6 hours, their combined pay was $120
                2J + 6B  = 120 --- ii 
Now, we should solve the expression; 
    Multiply equation ii by 2 and equation i by 1;
  
             4J + B = 75 ----- i    x 1  ;    4J + B  = 75          -- iii
             2J + 6B  = 120 --- ii  x 2 ;   4J + 12B  = 240    ---iv 
 Now, 
  equation iv - iii; 
                    11B  = 165
                       B  = $15
So, solving for J; 
           4J + B = 75
          4J + 15  = 75 
           4J  = 75 - 15  = 60 
           J  = $15