Question

(1) 7+ 10.5 +14+... + 84​

Answer 1

Step-by-step explanation:

Here, a = 7, d = 3.5 and last term = 84

Number of terms can be calculated as follows;

an=a+(n−1)dan=a+(n-1)d

Or, 84=7+(n−1)3.584=7+(n-1)3.5

Or, (n−1)3.5=84−7(n-1)3.5=84-7

Or, n−1=77÷3.5=22n-1=77÷3.5=22

Or, n=23

Answer 2

Answer:

7+10.5+14+84

=115.5

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