Question

find the sum of all integers between 84 and 719 which are multiple of 5

Answer 1

Answers

harshgori

Harshgori Expert

hey friend⭐

........

here is ur answer...

TO FIND :-the sum of multiples of 5 between 84 and 719

SOLUTION :-

multiples of 5 btw 84 and 719 forms A.P

abd in this AP WE HAVE:-

a = 85

d = 5

an or last term = 715

n = ?

sum of n terms = ?

so firt we habe to find no. of terms

so an = a+ (n-1) * d

→715 = 85 + (n-1) *5

→715 - 85 = (n-1) *5

→630/5 = n-1

→126+1 = n

no. of multiples of 5 btw 84 and 719= 127

so sum of multiples = n/2*(a+l)

→sum of multiples = 127/2* (85 +715)

→sum of multiples = 127/2 *800

→sum of multiples= 127*400

→sum of multiples= 50800

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HOPE IT HELPS..

PLS MARK ME AS BRAINLIEST...

Answer 2

Answer:

The sum of all integers between 84 and 719, which are multiples of 5 is 50800.

Step-by-step explanation:

Given :  

Integers between 84 and 719, which are multiples of 5 are 85, 90,95 ,...... 715

Here,  

a = 85, d = 5, an( l) = 715

By using the formula ,an = a + (n - 1)d

715 = 85 + (n -1)5

715 - 85 =  5(n -1)

630 = 5(n -1)

n -1 = 630/5

n -1 = 126

n = 126 + 1  

n = 127

By using the formula ,Sum of nth terms , Sn = n/2 [a + l]

⇒ S127 = 127/2 (a + l)

⇒ S127 = 127/2 (85 + 715)

⇒ S127 = 127/2 (800)  

⇒ S127  = 127 × 400

⇒ S127 = 50800

Hence, the sum of all integers between 84 and 719, which are multiples of 5 is 50800.

HOPE THIS ANSWER WILL HELP YOU….