You need to evaluate how much did the price of each share drop in the past year, hence, you need to subtract `$0.45` from original price of share, such that:
`P_i - $0.45 = P_f` (final price)
You also need to remember that `P_f` represents `64%` from `P_i` , such that:
`(P_f)/(P_i) = 64/100 => (P_f)/(P_i) = 0.64 => P_f = 0.64P_i`
Replacing `0.64P_i ` for` P_f` in equation `P_i - $0.45 = P_f` yields:
`P_i - $0.45 = 0.64P_i => P_i - 0.64P_i = $0.45`
`0.36P_i = $0.45 => P_i = 0.45/0.36 => P_i = $0.8`
Hence, evaluating how much did the price of each share drop in the past year yields the amount of ` $0.35` per share.