5. I have two coins. One is fair, and has a probability of coming up heads of.5.
The second is bent, and has a probability of coming up heads of. 75 .
If I toss each coin once, what is the probability that at least one of the coins will come up tails?
0.375
0.625
0.874
1.0

Step 1 ：We have two coins. One is fair, and has a probability of coming up heads of 0.5. The second is bent, and has a probability of coming up heads of 0.75.

Step 2 ：If we toss each coin once, we want to find the probability that at least one of the coins will come up tails.

Step 3 ：The probability of at least one coin coming up tails is the complement of the probability of both coins coming up heads.

Step 4 ：The probability of both coins coming up heads is the product of the individual probabilities of each coin coming up heads.

Step 5 ：So, we need to calculate the product of the probabilities of each coin coming up heads, and then subtract this from 1 to find the probability of at least one coin coming up tails.

Step 6 ：Let's denote the probability of the fair coin coming up heads as \(p_{\text{heads, fair}} = 0.5\) and the probability of the bent coin coming up heads as \(p_{\text{heads, bent}} = 0.75\).

Step 7 ：The probability of both coins coming up heads is \(p_{\text{both heads}} = p_{\text{heads, fair}} \times p_{\text{heads, bent}} = 0.375\).

Step 8 ：Finally, the probability of at least one coin coming up tails is \(p_{\text{at least one tails}} = 1 - p_{\text{both heads}} = 0.625\).

Step 9 ：Final Answer: The probability that at least one of the coins will come up tails is \(\boxed{0.625}\).