Question

What is the value of 8.0 km in inches?

(1 m = 1.094 yards & 1 yrd = 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 8 km = 8 $\times$1000 m
8 $\times$ 1000 m = 8 $\times$ 1000 $\times$ 1.09 4 yards
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