A penny weighs 5.8×10^-3 pounds. How many pennies are in a pile of pennies that weighs 3.596×10^4 pounds. Write the answer in scientific notation.

A. 6.2×10^6
B. 0.62×10^7
C. 6.2×10^8
D. 6.2×10-7

1 answer

To find how many pennies are in a pile that weighs \(3.596 \times 10^4\) pounds, we can divide the total weight of the pile by the weight of one penny.

Given:

  • Weight of one penny = \(5.8 \times 10^{-3}\) pounds
  • Total weight of the pile = \(3.596 \times 10^4\) pounds

The number of pennies \(N\) can be calculated as follows:

\[ N = \frac{3.596 \times 10^4}{5.8 \times 10^{-3}} \]

We can simplify this division step-by-step. First, divide the coefficients:

\[ \frac{3.596}{5.8} \approx 0.620 \]

Next, divide the powers of ten:

\[ \frac{10^4}{10^{-3}} = 10^{4 - (-3)} = 10^{4 + 3} = 10^7 \]

Now combine the results:

\[ N \approx 0.620 \times 10^7 \]

To express \(0.620\) in scientific notation, we can write it as \(6.2 \times 10^{-1}\). Therefore, we can multiply this with \(10^7\):

\[ N = 6.2 \times 10^{-1} \times 10^{7} = 6.2 \times 10^{7 - 1} = 6.2 \times 10^6 \]

Thus, the answer in scientific notation is:

\[ \boxed{6.2 \times 10^6} \]

This corresponds to option A.