7. A man starts his job with a certain monthly salary and a fixed increment every year. If his salary will be Rs. 11000 after 2 years and Rs. 14000 after 4 years of his service. What is his starting salary and what is the annual increment ?

Solution. Let starting salary of man be Rs. x and the fixed annual increment be Rs. y.

As per the first given condition,

x + 2y = 11000 ......(1)

As per the second given condition,

x + 4y = 14000 ......(2)

Subtracting (1) from (2),

x + 4y = 14000

x + 2y = 11000

(-)  (-)     (-)

2y = 3000

∴ y = 3000/2

∴ y = 1500

Substituting y = 1500 in equation (1)

x + 2y = 11000

∴ x + 2(1500) = 11000

∴ x + 3000 = 11000

∴ x = 11000 – 3000

∴ x = 8000

∴ The starting salary of man is Rs. 8000 and his fixed annual increment is Rs. 1500.