Answer:
<em>The third month</em>
Step-by-step explanation:
<u>Function Modeling</u>
We use mathematical models to approximate to the reality through numbers and symbols. It allows scientist to be able to compare, predict and take decisions based on the models.
We have two situations described as Aril and Dita donating Norwegian kroners in a monthly base.
Aril donated 150 kr the first month, and the cumulative number of kr donated increases by a factor of 2.5 each month. Being n the number of months, the function to model the donation is

Note that if n=0, A is the initial donation of 150 kr
Dita donated 300 kr the first month, and the cumulative kr donated increases by 400 kro each month. It's represented as a linear function

We must find a value of n such that

Or equivalently

This is an inequality that cannot be solved for n. We'll give some values until the condition is met

The inequality is not true

It's not true either

Now it's true, so the month where Aril's cumulative donation first exceed Dita's cumulative donation is the third