Question

$In ascending order, each positive number nn appears nn times in a sequence a_{n}an​ .\ \textless \ br /\ \textgreater \ 1, 2, 2, 3, 3, 3, 4, 4, 4, 4, \cdots.1,2,2,3,3,3,4,4,4,4,⋯.\ \textless \ br /\ \textgreater \ Find the following value.\ \textless \ br /\ \textgreater \ \Huge\text{ \rightarrow\displaystyle\sum^{7}_{k=1}a_{10^{k}}. }→k=1∑7​a10k​.$


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Answer 1

Answer:

28

Step-by-step explanation:

you can do it through at no need for ever and ever since last sum is easy

Answer 2

Answer:-

Let the number of chairs she purchased be n.

Cost of 1 chair =Rs.250

Cost of 1 teble =Rs.400

Now according to the question-

250×x+400×2=2800

250x+800=2800

⇒250x=2800−800

⇒x= 2000/250

→ x= 8.

Refer to the attachment -,-

#MichAditi✨✌️