brain teasers

[didghtara]

a lily pad doubles its size every day in 28 days it covers the pond how many days wil half the pond be covered

[Catron]

27 days. A half doubled equals one.

[beejay1124]

27

[dwil]

Isn't it 15? Half pond covered by day 14 then doubled on day 15.

[dwil]

Sorry. Just realised wrong logic. I'll shut up!

[didghtara]

thank you for your help i have another
a snail is at the bottom of a well the well is 30 meteres deep the snail advances 3 metres in one day during the night the snail slides back 2 metres how many days will it take the snail to reach the top ofthe well?

[Doc.Spock.1]

28 ( I think)