Units and Measurements question for NEET / JEE Main, with solution

Answer: (B) $(60 \pm 1.7)\ \text{cm}^2$

$A = 12.0\times 5.0 = 60\ \text{cm}^2$

For a product, the fractional errors add:
$$\frac{\Delta A}{A} = \frac{0.1}{12.0} + \frac{0.1}{5.0} = 0.0083 + 0.020 = 0.0283$$
$$\Delta A = 0.0283\times 60 \approx 1.7\ \text{cm}^2$$

So $A = (60 \pm 1.7)\ \text{cm}^2$.

Solution by Sreeraj P, M.Sc Physics