In the 5th year
For the first year, the salary is 1.2million = 1,200,000
For the second year, the salary is 1.2million + 75000 = 1,200,000 + 75,000 = 1,275,000
.
.
.
For the last year, the salary is 1.5million = 1,500,000
This gives the following sequence...
1,200,000 1,275,000 . . . 1,500,000
This follows an arithmetic progression with an increment of 75,000.
Remember that,
The last term, L, of an arithmetic progression is given by;
L = a + (n - 1)d ---------------(i)
Where;
a = first term of the sequence
n = number of terms in the sequence (which is the number of years)
d = the common difference or increment of the sequence
From the given sequence,
a = 1,200,000 [which is the first salary]
d = 75,000 [which is the increment in salary]
L = 1,500,000 [which is the maximum salary]
Substitute these values into equation (i) as follows;
1,500,000 = 1,200,00 + (n - 1) 75,000
1,500,000 - 1,200,000 = 75,000(n-1)
300,000 = 75,000(n - 1)
[tex]\frac{300,000}{75,000} = n - 1[/tex]
4 = n - 1
n = 5
Therefore, in the 5th year the maximum salary will be reached.
