Question

Add (7.8 × 105) + (2.4 × 105).

A) 10.2 × 106
B) 10.2 × 1010
C) 1.02 × 106
D) 1.02 × 105

Answer 1

To add (7.8 × 10⁵) + (2.4 × 10⁵), we combine the coefficients since the powers of ten are the same. The correct answer is D) 1.02 × 10⁶, which is the properly formatted result in scientific notation.

Step-by-step explanation:

To add the numbers (7.8 × 105) + (2.4 × 105), we can combine them by adding their coefficients because they have the same power of ten. The addition of the coefficients 7.8 and 2.4 gives us 10.2. Since the powers of ten are the same (both are 105), we do not change the power of ten in the result. Therefore, the sum is:

7.8 × 105 + 2.4 × 105 = (7.8 + 2.4) × 105 = 10.2 × 105

The correct answer is (D) 1.02 × 106 if we wanted the result in proper scientific notation, where the coefficient is a number between 1 and 10. To achieve this, we would adjust the coefficient by one decimal place to the right, 10.2 becomes 1.02, and increase the power of ten by one to maintain the correct value.