Mathematics for IGCSE & O level - Proportion (Section 1 - No. 42)
The variable *a* is directly proportional to *b*, and *a* = 6 when *b* = 2. Which of the following equations is correct?
a = b/3
a = 3b
b = 3a
a = 12b
解释
a = kb. Substitute a = 6 and b = 2 into the equation to find k = 3. Thus, a = 3b.