Question 1178780
X~N(18, 25) mean, sigma^2
z <(21-18)/5=3/5. That probability is 0.7257
z will be between 1/5 and 6/5. That probability is 0.3057
82% is a z of 0.9154
0.9154=(x-18)/5
x=18+4.58
22.58 cards.
At most it would be 22 cards.