Total number of houses = 14
number of houses on north side = 10
number of houses on west side = 14 - 10 = 4
number of ways of selecting any 4 houses = C(14 ,4)=1001
a.
number of ways of selecting all 4 houses on north side = C(10 ,4) =210
required probability = 210/ 1001 = 30 / 143
b.
number of ways of selecting all 4 houses on west side = C(4 ,4) = 1
required probability = 1/ 1001
c.
number of ways of selecting half of the houses on the west side and half on the north side = C(10 ,2)( C(4 ,2)) =45 (6) = 270
required probability = 270/ 1001
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