Answer:
The sum of all the numbers which are multiple of 5 between 5 an 1255 is 158,130
Step-by-step explanation:
In this question, we are asked to calculate the sum of all positive numbers that can be divided by 5 between 5 and 1255
To calculate this, we make use of the sum of an arithmetic progression
Mathematically, we have this as
Sn = n/2[a + L]
Where n is the number of terms which we do not know yet
a is the first term which is 5 and L is the last term which is 1255
Now to get n, we make use of the formula for finding the nth term of an arithmetic sequence
Tn = a+(n-1)d
where a is the first term which is 5 and d is the common difference which is also 5 with our Tn which is 1255
Substituting these values into the last term equation, we have
1255 = 5 + (n-1)5
1255 = 5 + 5n - 5
5n = 1255
n = 1255/5
n = 251
This means the number of terms we have in this arithmetic series is 251
Now we plug this n value into the sum equation
Thus,
Sn = 251/2(5 + 1255)
Sn = 251/2(1260)
Sn = 251 * 630
Sn = 158,130