Question

a box contains 28 bulbs of which 7 bulbs are defective a bulb is drawn randomly from the box . find the probability of picking a non - defective bulb​

Answer 1

$Number \:bulbs \: in \:the \: box = 28$

$Number \:of \\total \: possible \: outcomes = 28\: ---(1)$

$Number \:of \: defective \:bulbs = 7$

$Number \:of \: Non - defective \:bulbs\\ =Total \: bulbs - number \:of \: defective \: bulbs \\= 28 - 7 \\= 21$

$Number \: favourable \: outcomes = 21 \:--(2)$

$P( picking \: a \: defective \:bulb) = \frac{(2)}{(1)}\\= \frac{21}{28} \\= \frac{3}{4} \\= 0.75$

Therefore.,

$\red {P( picking \: a \: defective \:bulb)}\green {= 0.75 }$

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