If nPr = 720 and nCr = 120 then find the value of r.

Given: nPr = 720 & nCr = 120 Need to find: Value of r We know that, nPr = r! X nCr Putting the values, ⇒ 720 = r! X 120 ⇒ r! = 6 = 3! ⇒ r = 3.

Q9 of 68 Page 347

If ⁿP_r = 720 and ⁿC_r = 120 then find the value of r.

Given: ⁿP_r = 720 & ⁿC_r = 120 Need to find: Value of r We know that, ⁿP_r = r! X ⁿC_r Putting the values, ⇒ 720 = r! X 120 ⇒ r! = 6 = 3! ⇒ r = 3.

Write the value of (⁵C₁ + ⁵C₂ + ⁵C₃ + ⁵C₄ + ⁵C₅).

If ⁿ⁺¹C₃ = 2(ⁿC₂), find the value of n.

If ^(n2–n)C₂ = ^(n2–n)C₄ = 120 then find the value of n.

How many words are formed by 2 vowels and 3 consonants, taken from 4 vowels and 5 consonants?