1.One week a certain truck rental lot had a total of which were on the lot on Monday morning. If 50 percent of the trucks that were rented out during the week were returned to the lot or before Saturday morning of that week, and if there were at least 12 trucks on the lot that Saturday morning, what is the greatest number of different trucks that could have been rented out during the week?
2. 1,234+ 1,243+ 1,324+..........+ 4,321
the addition problem above shows four of the 24 differents integers that can be formed by using each of the digits 1,2,3 and 4 exactly once in each integer. What is the sum of these 24 integers?
I couldn't work out the problems above. anyone could help me? thank you very much.