Elitmus
Exam
General Ability
General Knowledge
What is the value of a^3 + b^3 ?
(I) a^2 + b^2 = 22
(II) ab=3
(a) A (b) B (c) C (d) D
Read Solution (Total 6)
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- a^3 + b^3=(a+b)(a^2-ab+b^2)
(a+b)^2=a^2+2ab+b^2
by solving 2nd equation=>(a+b)=(28)^1/2
by putting in equation 1 we get=>RHS=(28)^1/2*(22-3)=>100.53
- 9 years agoHelpfull: Yes(14) No(0)
- a^3 + b^3 = (a+b)(a^2 +b^2 -ab)
=(a+b)(22-3)
=(a+b)19
(a+b)^2 = a^2 + b^2 + 2ab
= 22 + 6
=28
=>a+b = (28)^(1/2)
ans = (28)^(1/2) * 19
=100.53 - 9 years agoHelpfull: Yes(7) No(0)
- option D is correct .......(plz refer http://www.elitmuszone.com/elitmus/data-sufficiency-problems-2/)
- 9 years agoHelpfull: Yes(2) No(0)
- option - d is Right answer.
bcoz after solving the above equations we won't get Unique value of a^3 + b^3.. - 9 years agoHelpfull: Yes(1) No(1)
- a^3 + b^3=(a+b)(a^2-ab+b^2)
(a+b)^2=a^2+2ab+b^2
by solving 2nd equation=>(a+b)=(28)^1/2
by putting in equation 1 we get=>RHS=(28)^1/2+(22-3)=>24.29 - 9 years agoHelpfull: Yes(0) No(5)
- Ans. C
By the help of both equation. - 9 years agoHelpfull: Yes(0) No(0)
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