E: 30/04 Win £250 holiday vouchers + hot air balloon ride (guessing effort)

One-Eye

Arriva Bus

If we were to tie gas filled balloons to our new, eco-friendly gas powered bus, how many do you reckon it would take for it to go up, up and away? Hundreds? Thousands?

Don't worry we're not looking for an exact number and we will give you a little bit of help......

Helium has a lifting force of 1 gram per litre and each balloon used is 30cm in diametre. To work it out exactly you would need this information as well as the weight of the bus (but we're not giving you that information - that would be too easy)

We are not looking for an exact number anyway, the closest guess to the number we have will win the prize!

Prize: If you're bang on (or the nearest), you'll win a UK weekend break for 2 that will include £250 worth of holiday vouchers so you can choose your destination and travel, and vouchers for a hot air ballooning ride that can be used at a number of locations around the UK.

My very rough calculations:- A 30cm spherical balloon would contain about 14 litres and thus lift 14g. A typical single decker bus would weigh around 7-9 tonnes so would need approx 500,000 - 650,000 balloons