Answer:
The final pressure inside the balloon will be
.
Explanation:
Given initial temperature of the balloon is 
And the final temperature of the balloon is 
Initially, the balloon is at atmospheric pressure
and volume be 
And the final pressure in the balloon is
and the volume be 
Also, it is given in the question that the final volume became twenty-two times the original volume.
We can write 
Now, using ideal gas equation.

Where,
is the gas constant. And
is moles of substance inside the balloon.
In our problem the value of
will be the same for both cases. Also,
is the gas constant.

Also, we have
from the question.

We need to convert the temperature from
to Kelvin.

Plug these values we get,

So, the final pressure inside the balloon will be
.