Two dices are thrown simultaneously what is the probability that both the dices have even number?

The sample space is 62 or 36. Take the 1st die rolled. It must start with a 2, 4, or 6. Likewise, the 2nd die rolled must be a 2, 4, or 6. So, with the 1st die at 2, the 2nd die could be 2, 4, or 6. The same holds true for the 4 & 6. There are 9 possible rolls then that are even & even. The probability is 9/36 or 1/4.