Question

Five digit numbers are formed using the digits 1, 2, 3, 4, 5, 6 and 8. What is the probability that they have even digits at both the ends

• A. $\frac { 2 } { 7 }$
• B. $\frac { 3 } { 7 }$
• C. $\frac { 4 } { 7 }$
• D. None of these

Answer 1

Answer: (A)

$\frac { 2 } { 7 }$

Answer 2

By using digits 1, 2, 3, 4, 5, 6 and 8, total 5 digits numbers = ${ } ^ { 7 } P _ { 5 }$

And number of ways to form the numbers, they have even digit at both ends $= 4 \times 3 \times { } ^ { 5 } P _ { 3 }$

$\therefore$ Probability .