1. **State the problem:** We are given the amount of money Francis has in his bank account over several days and need to find a rule for the amount of money $y$ in terms of days $x$.
2. **Analyze the data:** The table shows:
- Day 0: $27$
- Day 1: $70$
- Day 2: $113$
- Day 3: $156$
3. **Find the pattern:** Calculate the daily increase:
$$70 - 27 = 43$$
$$113 - 70 = 43$$
$$156 - 113 = 43$$
The amount increases by $43$ each day.
4. **Write the rule:** Since the amount increases by a constant $43$ each day, the relationship is linear:
$$y = mx + b$$
where $m$ is the rate of change (slope) and $b$ is the initial amount.
5. **Identify $m$ and $b$:**
- $m = 43$
- $b = 27$ (amount at day 0)
So the rule is:
$$y = 43x + 27$$
6. **Answer part b:** When will Francis have more than $1000$ dollars?
Set up inequality:
$$43x + 27 > 1000$$
7. **Solve the inequality:**
$$43x + 27 > 1000$$
$$43x > 1000 - 27$$
$$43x > 973$$
$$x > \frac{973}{43}$$
8. **Simplify the fraction:**
$$x > \frac{\cancel{973}}{\cancel{43}}$$
Since $43 \times 22 = 946$ and $43 \times 23 = 989$, $x$ is approximately $22.63$.
9. **Interpret the result:** Francis will have more than $1000$ dollars after about $23$ days (since $x$ must be a whole number of days).
**Final answers:**
- a. $y = 43x + 27$
- b. Francis will have more than $1000$ dollars after $23$ days.
Money Account 1Dad41
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