user62184: Does number of transactions in the block affect it's mining time? 
How and why?

user48884: The number of transaction in a block negligibly effects the mining time. The only effect is that more computations need to be done to calculate the merkle root during block construction, but that is a very small fraction of the number of calculations needed to be done during mining itself. Mining only hashes a fixed amount of data so including more or less transactions does not really make a difference.

62184: <p>Does number of transactions in the block affect it's mining time? </p>

<p>How and why?</p>
 48884: <p>The number of transaction in a block negligibly effects the mining time. The only effect is that more computations need to be done to calculate the merkle root during block construction, but that is a very small fraction of the number of calculations needed to be done during mining itself. Mining only hashes a fixed amount of data so including more or less transactions does not really make a difference.</p>
