Alright so what you want to do is add up the first and second day number of boxes, which would be 94, then you take 94 and subtract it by 150, (150-94). Once you do that you will have an answer of 56 so they would want to collect 56 more boxes on the third day. Hope this helps!!
How do I solve "The Cub Scouts want to collect more than 150 boxes of clothes to send to the flood victims. They collect 26 boxes on the first day and 68 boxes on the second day. How many boxes must they collect the third day to meet their goal?" (Linear Inequalities)