Question

How many terms are there between 250 and 1000 which are exactly divisible by 3 ?

Answer 1

Answer:

Solution. Clearly, the numbers between 250 and 1000 which are divisible by 3 are 252, 255, 258, …., 999. This is an A.P. with first term a = 252, common difference = 3 and last term = 999.

Answer 2

Step-by-step explanation:

The numbers between 250 and 1000 which are divisible by 3 are 252, 255, 258, ......,999

This is an A.P. whose first term a = 252, Common difference, d = 3 and Last term l=999

We Know that

l=a+(n-1)d

999=252+(n-1)3

999 - 252 = 3(n - 1)

n=250

We know that

S=n/2(a+l)

=250/2(252+999)

=125*1251

=156375

Hence, the required sum is 156375.

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