The probability of a man hitting a target is (1)/(10) . The least...

$p = \dfrac{1}{10}, q = \dfrac{9}{10}$

$P$ (not hitting in $n$ trials) $= {\left(\dfrac{9}{10}\right)}^{n}$

$∴$ $P$ (at least one hit)$= 1 - {\left(\dfrac{9}{10}\right)}^{n} > \dfrac{1}{4}$

$⇒$ ${\left(\dfrac{9}{10}\right)}^{n} < \dfrac{3}{4}$

${\left(0 .9\right)}^{n} < 0 . 75$

If $n = 3$ $⇒$ $0 . 729 < 0 . 75$ which is true.