Premium Online Home Tutors
3 Tutor System
Starting just at 265/hour
Answer :
Subba Rao’s starting salary = Rs 5000
It means, first term = a = 5000
He gets an increment of Rs 200 after every year.
Therefore, common difference = d = 200
His salary after 1 year = 5000 + 200 = Rs 5200
His salary after two years = 5200 + 200 = Rs 5400
Therefore, it is an AP of the form 5000, 5200, 5400, 5600… , 7000
We want to know in which year his income reaches Rs 7000.
Using formula \(a_n = a + (n - 1)d\) , to find \(n^{th}\) term of arithmetic progression,
\(\Rightarrow \) 7000 = 5000 + (n - 1) (200)
\(\Rightarrow \) 7000 = 5000 + 200n - 200
\(\Rightarrow \) 7000 – 5000 + 200 = 200n
\(\Rightarrow \) 2200 = 200n
\(\Rightarrow \) n = 11
It means after 11 years, Subba Rao’s income would be Rs 7000.