GabriellaKhingg
How is the answer C here ? Why do we need statement A? Please provide some explanation.
Statement two confirms y is 5 and not -5 ... Isn't that enough?
Posted from my mobile deviceNo.
If x^3*y^4 = 5000, what is the value of y ?Let's start by factoring 5000:
(1) x and y are integers.
Since y is in even power, then y can be 5 or -5.
Not sufficient.
(2) y is a positive number.
For ANY positive (integer or non-integer) value of y, there exists some x satisfying x^3y^4 = 5,000. For example:
\(y=\frac{1}{2}\) --> \(x = 20*\sqrt[3]{10}\)
\(y=1\) --> \(x=\sqrt[3]{5,000}\);
\(y=2\) --> \(x=\sqrt[3]{\frac{5,000}{16}}\);
\(y=3\) --> \(x=\sqrt[3]{\frac{5,000}{81}}\);
...
\(y=5\) --> \(x=2\);
...
\(y=10\) --> \(x=\sqrt[3]{\frac{5,000}{10,000}}\);
...
Not sufficient.
(1)+(2) Since both x and y are integers, and y > 0, then then from \(x^3y^4 = 2^35^4\), it follows that \(y=5\). Sufficient.
Answer: C.
Hope it's clear.