Question

solve 11 question from the data

Answer 1

(11).

Given : P(m + n,2) = 56 and P(m - n,2) = 30.

(i) Let m + n = a

= > a!/(a - 2)! = 56

= > a(a - 1)(a - 2)!/(a - 2)! = 56

= > a(a - 1) = 56

= > a(a - 1) = 8 * 7

= > a(a - 1) = 8 * (8 - 1)

= > a = 8.

Then, m + n = 8.     -------- (1)

Now,

(ii) Let m - n = b

= > b!/(b - 2)! = 30

= > b(b - 1)(b - 2)!/(b - 2)! = 30

= > b(b - 1) = 30

= > b(b - 1) = 6 * (6 - 1)

= > b = 6

Then, m - n = 6.     ------ (2)

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On solving (1) & (2), we get

= > m + n = 8

= > m - n = 6

    --------------

    2m = 14

       m = 7.

Substitute m = 7 in (1), we get

= > m + n = 8

= > 7 + n = 8

= > n = 8 - 7

= > n = 1.

Therefore, the value of m = 7, n = 1.

Hope this helps!

Answer 2

hope it helps you.........