Question 34 of 43advanced🔧 ApplyNumerical3 marks

Strike out 10 digits from the number 123451234512345 so that the remaining number is as large as possible.

Correct Answer

Given: The number 123451234512345 has 15 digits. Task: Strike out 10 digits to keep 5 digits for the largest possible number. Strategy: Keep the largest digits in the leftmost positions while maintaining left-to-right order. Analysis: The digits are 1,2,3,4,5,1,2,3,4,5,1,2,3,4,5. Three 5s are at positions 5,10,15. After picking 5(pos5) and 5(pos10), we need 3 more from positions 11-15: 2,3,4,5 — best is 3,4,5. Result: The largest possible number is 55345. Answer: 55345

Exercise: Figure it Out (Section 6) | Q: 4 | (Page Page 20)
For More Understanding

Explanation

To get the largest remaining number, we keep the largest digits in the leftmost positions while maintaining left-to-right order from the original number 123451234512345. The digits are: 1,2,3,4,5,1,2,3,4,5,1,2,3,4,5. We pick the first 5 at position 5, then the second 5 at position 10, then from positions 11-15 (1,2,3,4,5) we pick 3,4,5. This gives us 55345.

Solution Steps

  1. Step 1: The number 123451234512345 has 15 digits; we need to strike out 10 to keep 5.

  2. Step 2: To maximize, keep the largest digits in the leftmost positions while preserving left-to-right order.

  3. Step 3: Pick 5 (pos 5), 5 (pos 10), then from remaining positions 11-15 pick the 3 largest: 3, 4, 5.

  4. Step 4: The largest possible remaining number is 55345.

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