Can someone help me pls

Explanation:

Step 1) Put the numbers in order from smallest to biggest. That order would be {112, 121, 124, 137, 147, 156, 173, 189}

Step 2) There are 8 items in the list above. This is an even number of values. The middle most number is tied between 137 and 147 (slots 4 and 5). Average these two values to get (137+147)/2 = 284/2 = 142. The number 142 is exactly halfway between 137 and 147.