In an area having sandy soil, 60 small trees of a certain type were planted, and another 60 trees were planted in an area having clay soil. let x = the number of trees planted in sandy soil that survive 1 year and y = the number of trees planted in clay soil that survive 1 year. if the probability that a tree planted in sandy soil will survive 1 year is 0.6 and the probability of 1-year survival in clay soil is 0.5, compute an approximation to pi(−6 ≤ x − y ≤ 6) (do not bother with the continuity correction). (round your answer to four decimal places.)