How many pairs of positive integers x and y satisfy the equation x + 2y = 210? Each of the integers from 1 to 9 is to be placed in one of the 9 boxes in the picture so that any three numbers in consecutive boxes add to a multiple of 3. The numbers 7 and 9 have already been placed. In how many different ways can the remaining boxes be filled? 7 9 A triangular pyramid has edges of integer length. Four of these lengths are as shown in the diagram below. What is the sum of the lengths of the other two edges? 3 7 4 2