If y varies directly as x and y = 15 when x = 3, find y when x = 7.
A21
B35CORRECT
C28
D42
GCEMathematicsVariation and Inequalities2023
AI
Toaster Teacher
Why the answer is B, and why the others tempt you.
Since y varies directly as x, y = kx. Using y = 15 and x = 3 gives k = 15/3 = 5. When x = 7, y = 5 × 7 = 35.
Want this in Pidgin, Yoruba, Igbo or Hausa? Sign up free →
Practice more Mathematics questions
GCE Mathematics has thousands more questions like this — with Worked answers on every one.