What's the value of a^4 - b^4 ?
1. \(a^2 - b^2 = 16\)
2. \(a + b = 8\)
Appreciate it if somebody can help me in solving the above DS problem. An explanation will also be appreciated.
\(a^4 - b^4 = (a^2 - b^2)*(a^2 + b^2)\)
1. \(a^2-b^2 = 16\). Clearly insufficient as we do not know the value of \(a^2+b^2\).
2. \(a+b = 8\). Again insufficient as it does not provide any information about value of \(a-b\).
Together 1 and 2 are sufficient. How???
\(a^2-b^2 = 16\)
\((a-b)*(a+b) = 16\)
\(a-b = 2\) As we know that \(a+b = 8\). Now we can find the value of \(a & b\).
Thus answer is C.