Question

Median of the odd divisors of $720$ is

• A. the mean of $3^{rd}$ and $4^{th}$ item
• B. the mean of $4^{th}$ and $5^{th}$ item
• C. the mean of $5^{th}$ and $6^{th}$ item
• D. None of these

Answer 1

Answer: (A)

$720=2^4\times 3^2\times 5^1=2^a{3}^b{5}^c$
Number of odd divisors $=(b+1)(c+1)$ $=(2+1)(1+1)=6$
These six divisors are the factors of $45$, which are $1,3,5,9,15,45$
$\therefore$ Median is the mean of $3^{rd}$ and $4^{th}$ items