Asurvey showed that 74% of a nursery's mail-order customers spent more than $100 on plants each spring. predict how many of 125,000 mail-order customers will spend less then $100 on plants next spring.

From the survey: 74 % of a nursery`s mail-order customers spend more than $100 on plants each spring.
That means that less than $100 spends 26% mail-order customers ( 100 % - 74 % = 26 % ).
We have to calculate 26 % of 125,000:
0.26 * 125,000 = 32,500
32,500 mail-order customers will spend less than $100.