"65":{"bid":28,"cost":22.8,"volume":65},"15":{"bid":22.5,"cost":15.3,"volume":15}

x f(x) 2 5 3 ? 5 11

cost 15 15.5
cost 25 16.96
cost 35 18.42
cost 45 19.88
cost 55 21.34
cost 65 22.8


bid 15 22.5
bid 25 23.6
bid 35 24.7
bid 45 25.8
bid 55 26.9
bid 65 28