Question

Find the sum of all integers between 9 and 56 that are divisible by 5.

Answer 1

Answer:

325

Step-by-step explanation:

10+15+20+25+30+35+40+45+50+55

5(2+3+4+5+6+7+8+9+10+11)

add 1 and Subtract

5((1+2+3+4+5+6+7+8+9+10+11)-1)

5(((11×12)/2)-1) sum=n(n+1)/2

5(66-1)

65×5

325

Answer 2

The sum is 325

GIVEN

Numbers from 9 to 56

TO FIND

Sum of numbers divisible by 5

SOLUTION

We can simply solve the above problem as follows;

We know that any number that has a unit digit either 5 or 0 is divisible by 5

Numbers between 9-56 divisible by 5

First number will be 10 and last number will be 55

S = n/2 (First term + last term)

= 10/2 (10+55)

= 5 × 65

= 325

Hence, The answer is 325

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