find the sum of all numbers between 300 and 500 which are divisible by 7.
Answers
Answer:
Step-by-step explanation:
Hey,sup!
We'll solve this using Arithmetic Progression.
As per the question,
a=308. (First number divisible by 11 in the range)
d= 11.
l=495. (Last number divisible by 11 in the range)
A(n)= a+(n-1)d.
=>495=308+(n-1)11.
=>495-308=(n-1)11.
=>187=(n-1)11.
=>n-1= 187/11= 17.
=> n= 17+1 =18.
S(n)= n/2 (a+l).
S(18)= 18/2(308+495).
= 9 × 803.
= 7227.
Sum of all natural numbers between 300 and 500 which are divisible by 11 is 7227.
Hope it helps ya...
#Pari here...
to find - sum of number divisible by 7 between 300 and 500
solution
ap formed is
301 ,308 ,,,,,,,,,,,,,497
number of terms divisible by 7 are
497=301+(n-1)*7
497-319=(n-1)*7
196=(n-1)*7
28=(n-1)
29=n
sum of terms
=n/2(a+l)
=29/2(301+497)
=29/2(798)
=29*399
=11,571
thanks
hope its helpful