Answer:
Number of calculators n(C)=860
Number of defectives n(D)=9
The probability of a random number being defective=n(D)/n(C)
p=9/860.
converting this to a percentage gives us, 9/860×100%
=90/86
=45/43
=1.0465%
Therefore rounding this number to the nearest tenth gives us 1.0 % since the hundredth digit is 4 which is less than 5.
so, the probability of choosing a random defective calculator is 1.0%