z varies jointly as x and the square root of y. If z = 24 when x = 4 and y = 9, find z when x = 3 and y = 16.
A18
B24CORRECT
C12
D36
GCEMathematicsVariation and Inequalities2019
AI
Toaster Teacher
Why the answer is B, and why the others tempt you.
z = k·x·√y. Using z = 24, x = 4, y = 9: 24 = k × 4 × 3, so k = 2. When x = 3 and y = 16: z = 2 × 3 × √16 = 2 × 3 × 4 = 24.
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.