GMAT Practice Question: Each of the nine digits 0,1,1,4,5,6,8,8...
Question
Each of the nine digits 0,1,1,4,5,6,8,8, and 9 is used once to form 3 three-digit integers. What is the greatest possible sum of the 3 integers?
- 1,752
- 2,616
- 2,652
- 2,775
- 2,958
Topics: word problems, order, sums of digits
Solution
Step 1
We express the sum of the three 3-digit integers in terms of their hundreds, tens, and units digits using place values.
S = 100\times(h_1 + h_2 + h_3) + 10\times(t_1 + t_2 + t_3) + (u_1 + u_2 + u_3)
Step 2
We maximize the total by placing the largest digits in the highest-weight positions (hundreds), the next largest in the tens, and the smallest in the units.
h_1 + h_2 + h_3 = 9 + 8 + 8 t_1 + t_2 + t_3 = 6 + 5 + 4 u_1 + u_2 + u_3 = 1 + 1 + 0
Step 3
We substitute these sums into the expression for S and calculate.
S = 100\times25 + 10\times15 + 2 = 2500 + 150 + 2 = 2652
Answer
2652
