Answer:
M = 84 , r = 32
Step-by-step explanation:
Given M is directly proportional to r then the equation relating them is
M = kr ← k is the constant of proportion
To find k use the condition when r = 2, M = 14 , then
14 = 2k ( divide both sides by 2 )
7 = k
M = 7r ← equation of proportion
(a)
When r = 12
M = 7 × 12 = 84
(b)
When M = 224 , then
224 = 7r ( divide both sides by 7 )
32 = r
