Multiply 0.75 by 2.8×10^−5
A. 2.1×10^−6
B. 2.1×10^−5
C. 2.1×10^−4
D. 2.1×10^−7
To multiply 0.75 by 2.8×10^−5, you simply need to multiply the two numbers together. Let's break it down step by step:
Step 1: Multiply the decimal numbers
0.75 * 2.8 = 2.1
Step 2: Multiply the exponents
10^(-5) * 10^(0) = 10^(-5)
Step 3: Combine the result from Step 1 and Step 2
2.1 * 10^(-5) = 2.1×10^(-5)
Therefore, the correct answer is option B: 2.1×10^(-5).
To multiply two numbers written in scientific notation, you multiply their coefficients and add their exponents.
0.75 * 2.8 * 10^-5 = 2.1 * 10^(-2 - 5) = 2.1 * 10^(-7)
So the answer is D. 2.1×10^−7.
To multiply 0.75 by 2.8×10^−5, follow these steps:
Step 1: Multiply the decimal numbers without considering the exponent. Multiply 0.75 by 2.8, which gives you 2.1.
Step 2: Add the exponents. When multiplying numbers in scientific notation, you add the exponents. The exponent for 10 in the first number is 0, and in the second number, it is -5. Adding them gives you -5.
Step 3: Express the answer in scientific notation. The product of 0.75 and 2.8×10^−5 is 2.1×10^−5.
Therefore, the correct answer is B. 2.1×10^−5.