Question

If a and b vary inversely to other, then find the values of p, q, r ; x, y, z and l, m, n.

a	2	y	6	10
b	x	12.5	15	z

Answer 1

If a and b vary inversely to other.

i.e. ab = k ...(Constant)

For table,

a	2	y	6	10
b	x	12.5	15	z

If a = 6 and b = 15

Then, a × b = 6 × 15 = 90

 ⇒ k = 90

When a = 2 and b = x, then

ab = k

⇒ 2 × x = 90

⇒ x = `90/2` = 45

When a = y and b = 12.5, then

ab = k

∴ y × 12.5 = 90

⇒ y = `90/12.5` = 7.2

When a = 10 and b = z then

ab = k

⇒ 10 × z = 90

⇒ r = `90/10` = 9