Question

Julio measured the weight of a grain of sand and found it to be 3.5 times 10 Superscript negative 10 kg. He also measured the weight of one hair from his eyebrow and found that to be 7 times 10 Superscript negative 8 kg.
What is the total weight of both objects?
3.507 times 10 Superscript negative 10 kg
7.035 times 10 Superscript negative 10 kg
3.507 times 10 Superscript negative 8 kg
7.035 times 10 Superscript negative 8 kg

Answer 1

The total weight of both objects : 7.035 x 10⁻⁸ kg

Further explanation

Given

The weight of a grain of sand : 3.5 x 10⁻¹⁰ kg

The weight of one hair from his eyebrow : 7 x 10⁻⁸ kg

Required

The total weight of both objects

Solution

Scientific Notation consists of 2 parts  

1. the first part: the first digit followed by the decimal point  

2. The second part: the power of 10 (the exponents).which shows the number of digits after the decimal point  

To add/subtract, the exponents must be the same and then add/subtract the coefficient

• convert the largest exponent  (7 x 10⁻⁸)

7 x 10⁻⁸ = 700 x 10⁻¹⁰

• add the coefficients  

$\tt =(3.5+700)\times 10^{-10}\\\\=703.5\times 10^{-10}\\\\=7.035\times 10^{-8}$