The odds against a husband who is 45 years old, living till he is 70 are 7:5 and the odds against his wife who is now 36, living till she is 61 are 5:3. Find the probability that the couple will be alive 25 years hence, exactly one of them will be alive 25 years hence, none of them will be alive 25 years hence, at least one of them will be alive 25 years hence.

Explanation

To solve the problem step by step, we will calculate the probabilities for each scenario involving the husband and wife based on the given odds.

### Step 1: Calculate the probabilities for the husband and wife.

**Husband's Probability:**
- The odds against the husband living till 70 are 7:5.
- This means the probability of the husband living (H) is given by:
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