Question

how many multiples of 9 lie between 70 and 700? find the sum of these multiples of 9​

Answer 1

Answer:

Here series will be = 306, 315, 324, 333,...........693

So we have the first term a = 306 and d = 9 and last term l = 693

693 = 306 + (n-1)9

77 = 34 + (n-1)

n = 77 - 34 +1

= 44

Sum = n/2(a+l)

= 44/2(306+693)

= 22(999)

= 21978.

Hope this helps!

Step-by-step explanation:

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