Answer : The final volume of the helium in the balloon at the higher altitude is 5.55 L
Explanation :
Boyle's Law : It is defined as the pressure of the gas is inversely proportional to the volume of the gas at constant temperature and number of moles.

or,

where,
= initial pressure of gas =

= final pressure of gas =

= initial volume of gas = 4.70 L
= final volume of gas = ?
Now put all the given values in the above equation, we get:


Therefore, the final volume of the helium in the balloon at the higher altitude is 5.55 L