Question

Find sum of those integer from 1 to 500 which multiple of 2 and 5

Answer 1

Firstly find the LCM of 2and5

is 10

Now, we know that multiple of 10 is also the multiple of 2 and 5

so it makes series form

10,20,30,..........,490

a=10

d=20-10=10

total no. of terms =n

an=490

an=a+(n-1)d

490=10+(n-1)10

480=(n-1)10

480=10n-10

490=10n

49=n

Sum of n terms

Sn=n/2(a+l)

S49=49/2(10+490)

=49/2*500=12250

Answer 2

Answer:

12750 is the answer......