The law of detachment and the law of syllogism to draw a conclusion from the given statements: franz is taller than isabel. isabel is shorter than ellen. janina is taller than franz.

             A ≡ number is a multiple of 64
B ≡ number is a multiple of 8
C ≡ number is a multiple of 2

Using (A → B) ∩ (B → C) → (A → C), the direct conclusion is:

If a number is a multiple of 64, then it is a multiple of 2.

Using (A → C) → (~C → ~A), the contrapositive of the direct conclusion is:

If a number is not a multiple of 2, then the number is not a multiple of 64.

Thus, both d and c are valid, syllogistic conclusions.

As a decimal, 11/20 is .55.