Given data:

The number of passengers vehicles (N) registered in Country U is 260 million.

The storage of battery (w) in average vehicle is 540 Wh.

Calculation:

The total energy stored in Country U’s passenger vehicle is calculated as follows,

wtotal=N×w (1)

Here,

N is the number of passenger vehicles, and

w is the average energy stored in vehicle.

Substitute 540 Wh for w, and 260 million for N in equation (1) to find wtotal.

wtotal=(260 million)(540 Wh)=(260×106)(540 Wh)                              {∵1 million=106}=1.404×1011 Wh=1.404×1011×10−9×109 Wh

Simplify the above equation to find wtotal.

wtotal=140.4×109 Wh=140.4 GWh                                     {∵1 G=109}

Conclusion:

Thus, the value of total energy stored in Country U’s passenger vehicle is 140.4 GWh.