2026 · Q13
If x varies directly as y, then which of the following is/are correct?
I. (x^2 + y^2) varies directly as y^2.
II. (x^3/y^4) varies directly as y.
Select the answer using the code given below:
Elementary MathematicsRatio and Proportion
- AI only
- BII only
- CBoth I and II
- DNeither I nor II
Explanation
Since x varies directly as y, write x=ky. Then x²+y²=(k²+1)y², which varies directly as y², so I is correct. But x³/y⁴=k³/y, which varies as 1/y rather than as y, so II is incorrect. Only I is correct, option A.