A man firing at a distant target has 10% chance of hitting the taget in one shot.The number of times he must fire at the target to have about 50%chance of hitting the target is

a. 11

b.9

c. 7d. 5

prob of hitting target is 1/10

loosing target is 9/10

so in order to succed in nth shot, he has to fail in (n-1) shots and succed in nth shot

so , here (9/10)^(n-1)*(1/10) = (1/2)

on solving n comes nearly to 7 where chace of hitting is arnd 53%

so, n = 7

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regards

Ramesh