Answer:
<h2>The manager has to by 2,000 sodas and 2,500 water drinks.</h2>
Step-by-step explanation:
From the problem we know that the manage needs to buy a total of 4,500 drinks between water and soda, this can be expressed as

Where
is water and
is soda.
Then, it's given that there is needed 25% more water than soda, which can be expressed as

Which means that water represents 125% of the soda, because we must include the additional 25% more water over soda.
Then, we replace the second relation into the first one

Now, we replace this value in one equation to obtain the other one

Therefore, the manager has to by 2,000 sodas and 2,500 water drinks.