Question

For the following table, find the values of 𝑎, 𝑏 and 𝑐:

Number of men	130	70	𝑏	120
Number of days required to do the same work	𝑎	39	30	𝑐

Answer 1

It is a case of inverse variation:

∴ 130 × a = 70 × 39 = b × 30 = 120 × c

Taking,

130 × a = 70 × 39

⇒ a = `(70×39)/130`

⇒ a = 7 × 3

⇒ a = 21

Taking,

70 × 39 = b × 30

⇒ b = `(70×39)/30`

⇒ b = 7 × 13

⇒ b = 91

Taking,

70 × 39 = 120 × c

⇒ c = `(70×39)/120`

⇒ c = 22.75

Hence, the value of a = 21, b = 91 and c = 22.75