If m is proportional to n and m = 5 when n = 4, then what is the value of m when n = 18?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 22.5
When m is proportional to n, \(m=kn\) for a fixed constant \(k\), so the ratio \(\frac{m}{n}\) stays the same for every pair of values.
\(\displaystyle k=\frac{m}{n}=\frac{5}{4}\)
When \(n=18\): \(\displaystyle m=\frac{5}{4}\times18=22.5\)