Question

The value of $8.0km$ in inches is

(1 m = 1.094 yards & 1 yard = 36 inches)

• A. $3.15\times {10}^5$
• B. $3.2\times {10}^5$
• C. $3.1\times {10}^5$
• D. $3.3\times {10}^5$

Answer 1

The correct option is C $3.1\times {10}^5$

We know that,
$8km=(8\times 1000)m$
$(8\times 1000)m=(8\times 1000\times 1.094)yards=(8\times 1000\times 1.094\times 36)inches=3.15\times {10}^{5}inches$
But since 8.0 has two significant digits we report the answer in two significant figures
i.e., $3.1\times$ ${10}^{5}inches$