a box contains 25 electric bulbs, out of which 4 are defective. two bulbs are chosen at random from this box. the probability that at least one of these is defective is
Options.
A) 3 / 10 B) 7 / 19 C) 12 / 19 D) 21 / 95 E) none
<gadget id="calculator">25 - 4</gadget>
<output>21</output>

<gadget id="calculator">binomial(21, 2)</gadget>
<output>210</output>

<gadget id="calculator">binomial(25, 2)</gadget>
<output>300</output>

<gadget id="calculator">210 / 300</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">1 - (7/10)</gadget>
<output>3/10 = around 0.3</output>

<result>A</result>
a box contains 25 electric bulbs, out of which 4 are defective. two bulbs are chosen at random from this box. the probability that at least one of these is defective is
subtract(const_1, divide(choose(subtract(25, 4), const_2), choose(25, const_2)))
"solution p ( none is defective ) = 21 c 2 / 25 c 2 = 7 / 10 p ( at least one is defective ) = ( 1 - 7 / 10 ) = 3 / 10 . answer a"