find the sum of all numbers 100 and 400 are divisible by 7
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Answered by
1
Answer:
the sequence will be 105 ,112 ,119 ......
Step-by-step explanation:
a =T1 = 105
d= t2 - t1 = 7
t3 - t2 = 7
I will guide you . I a. in hurry
Find tn of the last term by the formula tn=a+ n-1 ×d
then you will get tn ..
the value you get in tn put in sn and here's your answer ...
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Answered by
1
Answer:
10,836
Step-by-step explanation:
numbers divisible by 7 from 100 to 400.
105,112,119,.......,399
a=105
d=7
tn=399
tn=a+(n-1)d
399=105+(n-1)7
399=105+7n-7
399=98+7n
399-98=7n
n=43
Sn=n/2 [2a+(n-1)d]
=43/2 [2×105+(43-1)7]
=21.5 [210+294]
=21.5×504
=10,836
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