If Tania bought 4 pounds more of pears then Wilma and together they bought 18 just divided 18 in half and you get 9. so first take 2 pounds from 9 and give 2 pounds to another 9. the one we took away equals 7 and the one we added equals 11 and 11 + 7 = 18 so Wilma bought 7 pounds of pears.
so your answer is 7 pounds of pears.