If a and b vary inversely to each other.

i.e. ab = k(constant)

For table (a),

If a = 6 and b = 18

Then, a

⇒ k = 108

When a = 8 and b = p, then

ab = k

⇒ 8×p = 108

⇒

When a = q and b = 39, then

ab = k

∴ q× 39 = 108

⇒

When a = 25 and b = r, then

ab = k

⇒ 25 × r = 108

⇒

For table (b),

If a = 6 and b = 15

Then, a

⇒ k = 90

When a = 2 and b = x, then

ab = k

⇒ 2× x = 90

⇒

When a = y and b = 12.5, then

ab = k

∴ y× 12.5 = 90

⇒

When a = 10 and b = z then

ab = k

⇒ 10 × z = 90

⇒

For table (c),

If a = 6 and b = 1

Then, a

⇒ k = 60

When a = l and b = 5, then

ab = k

⇒ l×5 = 60

⇒

When a = 9 and b = m, then

ab = k

∴ 9× m = 60

⇒

When a = n and b = 25, then

ab = k

⇒ n × 25 = 60

⇒