Answer:
3.458 × 10¹⁷
Explanation:
We multiply the amount of salt per liter, 3.5×10⁻², by the amount of sea water in the South China Sea, 9.88×10¹⁸:
(3.5×10⁻²)(9.88×10¹⁸)
Multiplication is commutative; this means we can switch around the numbers we are multiplying:
(3.5×9.88)(10⁻²×10¹⁸)
Multiplying the numbers in the first set of parentheses, we have 34.58.
To multiply the powers of 10, we use the product property; it states that if we multiply powers that have the same base, we add their exponents:
10⁻²×10¹⁸ = 10⁻²⁺¹⁸ = 10¹⁶
This gives us 34.58 × 10¹⁶. In scientific notation, the decimal must be behind the first non-zero digit; this gives us 3.458. When we move the decimal again, we add 1 to the exponent; this gives us 3.458 × 10¹⁷
