Giant kelp is one of the fastest-growing organisms on the planet. Desmond told his little brother that kelp grows about $1.38 \times 10^{-2}$ feet per minute. What would be the most appropriate unit for Desmond to use instead of feet per minute? $\newline$ Choices: $\newline$ (A) inches per minute $\newline$ (B) feet per second $\newline$ (C) feet per hour $\newline$ (D) feet per day

Full solution

Q. Giant kelp is one of the fastest-growing organisms on the planet. Desmond told his little brother that kelp grows about

1.38 \times 10^{-2}

feet per minute. What would be the most appropriate unit for Desmond to use instead of feet per minute?

\newline

Choices:

\newline

(A) inches per minute

\newline

(B) feet per second

\newline

\newline

(D) feet per day

Convert to inches: Kelp grows $1.38 \times 10^{-2}$ feet per minute. Convert feet to inches because there are $12$ inches in a foot.
Multiply by $12$ : $1.38 \times 10^{-2}$ feet per minute $\times 12$ inches/foot = $1.38 \times 10^{-2} \times 12$ inches per minute.
Write in scientific notation: Do the multiplication: $1.38 \times 12 = 16.56$ .
Simplify notation: Now, write it in scientific notation: $16.56 \times 10^{-2}$ inches per minute.
Choose appropriate unit: Simplify the scientific notation: $16.56 \times 10^{-2} = 0.1656$ inches per minute.
Choose appropriate unit: Simplify the scientific notation: $16.56 \times 10^{-2} = 0.1656$ inches per minute.Choose the most appropriate unit from the choices given. Inches per minute makes the most sense because the number is small and manageable.