Umbrellas are highly seasonal. their highest selling month is 325% of their lowest selling month. during their lowest selling month, they sell 980 units. how many units do they sell during the peak month?

We know from the givens that "Their highest selling month is 325% of their lowest selling month.".
Transforming this into an equation, we get:
highest selling month = 3.25 x lowest selling month

We are also given the amount in the lowest selling month as 980 units.So, all we need to do is substitute in the equation to get the number of units in the highest selling month as follows:
highest selling month = 3.25 x 980 = 3185 units