Hi there!
Since there is a 50% chance of any coin landing on heads and a 50% chance of any coin landing on tails, the chance that all 3 coins land on either heads or tails (the same side) is 50% * 50% * 50%.
50% * 50% * 50%
= 0.5 * 0.5 * 0.5
= 0.25 * 0.5
= 0.125
Now, we need to convert into a percentage:
0.125 = 12.5%
So, the answer is 12.5%.
Hope this helps!