Bissoy.com
Doctors Medicines MCQs Q&A

  1. III and either I or II
  2. I and either II or III
  3. II and either I or III
  4. Any two
  5. All three
4 views

1 Answers

Option 4 : Any two

We know, (a3 + b3) = (a + b)3 - 3ab (a + b)

Considering statements I and II,

⇒ (a + b) 2 = a2 + b2 + 2ab

⇒ 92 = 41 + 2ab

⇒ ab = (81 - 41)/2 = 20

⇒ (a3 + b3) = (9)3 - 3(20) (9) = 729 - 540 = 189

Considering statements I and III,

⇒ (a3 + b3) = (9)3 - 3(20) (9) = 729 - 540 = 189

Considering statements II and III,

⇒ (a + b)2 = a2 + b2 + 2ab = 41 + 2(20) = 81

⇒ (a + b) = √81 = 9

⇒ (a3 + b3) = (9)3 - 3(20) (9) = 729 - 540 = 189

∴ The question can be answered using any two of the given statements
4 views

Related Questions