fun charge_time kO uF =
let val r1 = kO * 1000.0
val r2 = 10.0 * 1000.0
val c1 = uF / 1000000.0
in 1.05 * c1 * (r1 + r2) end

map (fn k => charge_time k 1000.0) [0.0, 100.0, 200.0, 500.0, 1000.0]
SML is so comfy