If (x – 5)(y 6)(z – 8) = 1331, then the minimum value of x y z is:







1)

40








2)

33








3)

19








4)

45








5)

Not unique
















Correct Answer: 1





Your Answer: Not Attempted





Course: CAT Quantitative







Answer Description


The minimum Sum is obtained when (x – 5) = (y 6) = (z – 8)

Hence (x – 5) = (y 6) = (z – 8) = 11

=> x = 16, y = 5, z = 19

Thus (x y z) = 40
















Q20)







If x y z = 21, then the maximum value of (x – 6)(y 7) (z – 4) is:







1)

343








2)

216








3)

125








4)

64








5)

None of these
















Correct Answer: 2





Your Answer: Not Attempted





Course: CAT Quantitative







Answer Description


(x – 6)(y 7)(z – 4) will be maximum only when

(x – 6) = (y 7) = (z – 4) = k (say) for a given value of (x y z) = 21

=> x = k 6

=> y = k – 7

=> z = k 4

x y z = 21

=>(k 6) (k – 7) (k 4) = 21

=>3k 3 = 21

=>k = 6

 

Therefore, (x – 6).(y 7)(z – 4) = k³ = (6)³ = 216

i didnt understand the answer plz clarifythnx