There are no options listed to choose the best estimate from so I am not sure if you are looking for the closest 10s, 50s or 100s.
Here is how you approach this problem.
STEP 1:
Subtract number of total tickets purchased from total number of seats.
=total seats - tickets purchased
=325 - 187
=138 empty seats
STEP 2:
140 would be the estimate if estimating by 10s. 150 would be the estimate if estimating by 50s. 100 would be the estimate if estimating by the 100s.
Hope this helps! :)
