Question

If a³ – b³ = 158 and a³ + b³ = 185. Find the value of a/b.
1. 3/7
2. 7/3
3. 7/√2
4. 3/√2

Answer 1

Correct Answer - Option 2 : 7/3

Given: 

a3 – b3 = 158 

a3 + b3 = 185

Calculation:

a3 – b3 = 158      ---- (1)

a3 + b3 = 185      ---- (2)

By adding equation (1) and equation (2)

⇒ 2a³ = 343

⇒ a = 7/(2)^1/3

By subtracting equation (1) from equation (2)

⇒ 2b³ = 27

⇒  b = 3/(2)^1/3

⇒ a/b = (7/2^1/3)/(3/21/3)

⇒ a/b = 7/3

∴ The value of a/b is 7/3.