Question

If ^m+nP₂ = 90 and ^m–nP₂ = 30, then (m, n) is given by ______.

विकल्प

• (7, 3)

• (16, 8)

• (9, 2)

• (8, 2)

Answer 1

If ^m+nP₂ = 90 and ^m–nP₂ = 30, then (m, n) is given by (8, 2).

Explanation:

⇒ (m + n)(m + n – 1) = 90 = 10 × 9

⇒ m + n = 10  ...(1)

and (m – n)(m – n – 1) = 30 = 6 × 5  

⇒ m – n = 6  ...(2)

Solving (1) and (2) we get

m = 8,

n = 2