Answer:
a) A = kB
b) 20
c) 9
Step-by-step explanation:
A is directly proportional to B when A = 12, B = 3
a) find a formula for A in terms of B
A ∝ B
A = kB
Where k is constant of proportionality
when A = 12, B = 3
12 = 3k
k = 12/3
k = 4
b) find the value of A when B = 5
A = kB
k = 4
A = 4 × 5
A = 20
c) find the value of B when A = 36
k = 4
A = kB
B = A/k
B = 36/4
B = 9
