An investment of $1 was put in an account. Every 8 years, the money doubled. No additional money was added to the account. Would the expression $1 \times 2 \times 2 \times 2 \times 2 \times 2 \times 2$ correctly represent how much was in the investment account after 48 years? Explain.
An investment of \(\$1\) doubles every \(8\) years. To determine the amount in the account after \(48\) years, we calculate how many times the money doubles. The number of doubling periods \(n\) is given by the total time divided by the time it takes for one doubling:
\[n = \frac{48 \text{ years}}{8 \text{ years/period}} = 6 \text{ periods}\]
The growth of the investment follows an exponential model \(A = P \cdot 2^n\), where \(P\) is the initial principal and \(n\) is the number of doubling periods. Substituting our known values \(P = \$1\) and \(n = 6\), the amount after \(48\) years is:
\[A = 1 \cdot 2^6 = 2^6\]
The provided expression is \(1 \times 2 \times 2 \times 2 \times 2 \times 2 \times 2\). We can rewrite this as:
\[1 \times 2^6\]
Since we established that the amount after \(48\) years is \(1 \cdot 2^6\), we see that the expression correctly matches the growth model. The number of times the investment doubles is exactly \(6\), which corresponds to the six factors of \(2\) in the expression provided. Thus, the expression correctly represents the total amount in the account after \(48\) years.
The expression \(1 \times 2 \times 2 \times 2 \times 2 \times 2 \times 2\) accurately calculates the amount after \(48\) years because it represents the initial \(\$1\) being doubled \(6\) times over a span of \(48\) years. The final amount in the account is \(\$64\). Therefore, the expression is correct. \(\boxed{\text{Yes}}\)
Understanding compound growth is essential in finance, such as when calculating interest in a savings account or the growth of an investment over time. For example, if you place \(\$100\) in an account that doubles every \(10\) years, you can use the same logic to calculate the value after \(30\) years: \(100 \times 2^3 = 100 \times 8 = \$800\). This helps in planning for long-term financial goals and understanding how exponential growth affects your savings.