Question

Evaluate (5.15×10^−1)×(1.27×10^11).

a) 6.525×10^10
b) 6.5405×10^11
c) 65.25
d) 65.405×10^11

Answer 1

To evaluate the expression (5.15×10^-1)×(1.27×10^11), we multiply the decimal parts and add the exponents of 10, resulting in 6.5405, which is expressed in proper scientific notation as b) 6.5405×10^11.

Step-by-step explanation:

The question asks to evaluate the expression (5.15×10−1)×(1.27×1011) and determine the correct answer in scientific notation. To do this, we multiply the decimal parts (5.15 and 1.27) and then add the exponents of 10 (−1 and 11).

First, multiply the decimal parts:
5.15 × 1.27 = 6.5405.

Next, add the exponents of 10:
−1 + 11 = 10.

Now, combine the two parts in scientific notation:
6.5405 × 1010. Since we want to express it in proper scientific notation, we must have one non-zero digit before the decimal point, so we adjust the value:
6.54×1011 (after rounding to three significant figures).

Therefore, the correct answer is b) 6.5405×1011.