@Simi_2210_ You could also look at it in a simpler method which the answer would be 5, sister a b c d and me
Sister a has b c d and me as sisters
Sister b has a c d and me as sisters
Sister c has a b d and me as sisters
Sister d has a b c and me as sisters
Which would make the answer 5
@Kinza1278 The answer is 20, two unseen holes for the arm, the neck hole, the body hole, two wrist holes, and 14 holes in the shirt itself because the holes go all the way through so the 7 holes you see are doubles.