Answer:
40%
Explanation:
Remember that guanine always pairs with cytosine, and thymine always pairs with adenine. That means that any time there is a guanine, there is always a cytosine.
If there are 10% guanines, then there are 10% cytosines. That means the total of guanines and cytosines is 20%.
The other 2 bases (thymine and adenine) have to make up the rest of the bases. That means they have to make up 100-20 = 80%.
Again, there will be equal amounts of thymine and adenine, so 80%/2 = 40%.
