JAMB 2002 · UME · Q6

Without using tables, evaluate $(343)^{\frac13} \times (0.14)^{-1} \times (25)^{-\frac12}$ .

Worked solution (try it first)

$(343)^{\frac13}$ is the cube root of 343, which is 7.
$(0.14)^{-1}$ is the reciprocal of 0.14: $\frac{1}{0.14} = \frac{100}{14}$
$= \frac{50}{7}$ .
$(25)^{-\frac12} = \frac{1}{\sqrt{25}}$
$= \frac15$ .
Multiply: $7 \times \frac{50}{7} \times \frac15 = 10$ , option C.