Answer
$P$(All 3 siblings kidney matches)=$1.5625$%
Work Step by Step
Event A: 1st sibling kidney matches receiver.
Event B: 2nd sibling kidney matches receiver.
Event C: 3rd sibling kidney matches receiver.
$P$(All kidneys match)= $P$(A ∩ B ∩ C)
$P$(A ∩ B ∩ C) = $P$(A) * $P$(B) * $P$(C)
$P$(A ∩ B ∩ C) = $0.25*0.25*0.25 = 0.015625 =1.5625$%.
