IAS (CAS) 210KTS FL140/-5ºC = TAS 262 KTS
Wind component = -35 KTS
Groundspeed = 227 KTS
150nm at 227 KTS GS = 39.6 mins
150nm in 44.6 mins = 202 KTS required GS
New TAS required = 202 + 35 = 237 KTS.
TAS 237 KTS FL140/-5ºC = New IAS 190 KTS
Old IAS = 210 KTS
New IAS = 190 KTS
Speed reduction = 210 - 190 = 20 KTS