Why is Lent 40 Days Before Easter?

Today is the first Sunday of Lent and the "Lenten season" that began on March 2, with Ash Wednesday -- defined as "a season of penance, reflection, and fasting which prepares us for Christ's Resurrection on Easter Sunday, through which we attain redemption" -- according to Catholic.org. And, since today's topic explores the biblical significance of the number 40 -- count 40 days from Ash Wednesday, and that is April 10 -- Palm Sunday. On that day, we commemorate when Jesus entered Jerusalem and received a palm-waving king's welcome. Yet, five days later, he was crucified on Good Friday and then gloriously resurrected on Easter Sunday.