a monkey ascends a greased pole 12 metres high . he ascends 2 metres in first minute and slips down 1 metre in the alternate minute . in which minute , he reaches the top ?
in 2 minutes , he ascends = 1 metre ∴ 10 metres , he ascends in 20 minutes . ∴ he reaches the top in 21 st minute . answer b
subtract(multiply(2, 12), 1)