In a winter season let us take the temperature of Ooty from Monday to Friday to be in A.P. The sum of temperatures from Monday to Wednesday is 0° C and the sum of the temperatures from Wednesday to Friday is 18° C. Find the temperature on each of the five days.

Solution :

Let the temperature of Ooty from Monday to Friday are

a - 2d, a - d, a, a + d , a + 2d

a - 2d + a - d + a = 0

3a - 3d = 0

a - d = 0 ---(1)

a + a + d + a + 2d = 18

3a + 3d = 18

a + d = 6 ---(2)

(1) + (2)

a + a = 6

2a = 6

a = 3

By applying the value of a in (1), we get

3 + d = 6

d = 6 - 3

d = 3