Question

Three digit numbers are formed using only 7 and 5. Only one of the digits can be used twice. How many 3 digit numbers can be formed and which is the greatest? ​

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• A. 3 & 775​
• B. 6 & 775​
• C. 6 & 757​
• D. 3 & 757​

Answer 1

The correct option is B 6 & 775​

3 digit numbers that can be formed by repetition of 5 are: 557, 575, 755​

​3 digit numbers that can be formed by repetition of 7 are: 775, 757. 577​

​Therefore, total number of 3 digit numbers that can be formed​=6​

The greatest number among the numbers formed is 775.​