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There are two sets of parallel lines, th...

There are two sets of parallel lines, their equations being `x cos alpha+y sin alpha=p` and `x sin alpha- y cos alpha=p` , `p=1,2,3,….n` and `alpha in (0,pi//2)`. If the number of rectangles formed by these two sets of lines is `225`, then the value of `n` is equals to (a) 4 (b) 5 (c) 6 (d) 7

A

`4`

B

`5`

C

`6`

D

`7`

Text Solution

Verified by Experts

The correct Answer is:
C
`(c )` `"^(n)C_(2)*^(n)C_(2)=225impliesn=6`
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