Let x be a constant. The 5th term of an arithmetic sequence is a5=16x+11. The 9th term of the sequence is a9=28x+19. Find the fi
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Answer:
The man's income by the 20th week will be Rs. 1770
Step-by-step explanation:
Given that the income of man in first week is Rs. 60
It is also mentioned that the income increases every week then the previous one.
which means the weekly incomes will be like:
60,63,66,69.....
As the common difference of terms is same i.e. 3, it forms an arithmetic sequence.
Where
The general formula for arithmetic sequence is:
Putting the values of d and a_1 we get
This is the general formula to find the income of any week. Now for 20th week,
n = 20
The income for 20th week is 117.
As we have to find the total income for 20 weeks
We will use the summation formula for arithmetic sequence.
Putting the values
Hence,
The man's income by the 20th week will be Rs. 1770