1 vote

Five numbers $10,7,5,4$ and $2$ are to be arranged in a sequence from left to right following the directions given below:

- No two odd or even numbers are next to each other.
- The second number from the left is exactly half of the left-most number.
- The middle number is exactly twice the right-most number.

Which is the second number from the right?

- $2$
- $4$
- $7$
- $10$

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Best answer

- No two odd or even numbers are next to each other.
- The second number from the left is exactly half of the left-most number.

So, the left most number must be even and its half must be odd which comes next. Only options are $10,5$ - The middle number is exactly twice the right-most number.

Middle number must be even and only options left are $2$ and $4$. Since $1$ is not there, $4$ must be the middle and $2$ the right most.

Thus we get $$10\quad 5 \quad 4 \quad 7 \quad 2$$

Required answer is $7.$

Option C.