Question
Question: If <sup>56</sup>P<sub>r+6</sub>: <sup>54</sup>P<sub>r+3</sub> = 30800:1, then r =...
If 56Pr+6: 54Pr+3 = 30800:1, then r =
A
31
B
41
C
51
D
None of these
Answer
41
Explanation
Solution
$$= $\frac{30800}{1}$⇒ 56 x 55 x (51-r) = 30800 ⇒ r = 41.