The hour hand is 30 mm hope this is right
(2n-1) /(n+9)
hope it can help u
If n is rational, it means that

Therefore when we do n² we can write it as

Remember that the product of two integer numbers is also an integer, therefore we can guarantee that

Then we can confirm that n² is the quotient of two integers and the denominator is not zero, therefore, n² is always rational, it cannot be an irrational number
Answer:
The answer should be choice D.
HOPE THIS HELPS! :)
2/3 hour =2/3×60 min=40 min
2/3 hour=2/3×3600 seconds=2400seconds