The sum of the factors of a number is 124. What is the number?a)Number...
Any number of the form paqbrc will have (a + 1) (b + 1)(c + 1) factors, where p, q, r are prime. (This is a very important idea)
For any number N of the form paqbrc, the sum of the factors will (1+p1+p2+…+pa)(1+q1+q2+…+qb) (1+r1+r2+…+rc)
Sum of factors of number N is 124. 124 can be factorized as 22 × 31. It can be written as 4 × 31, or 2 × 62 or 1 × 124.
2 cannot be written as (1+p1+p2+…+pa) for any value of p.
4 can be written as (1 + 3)
So, we need to see if 31 can be written in that form.
The interesting bit here is that 31 can be written in two different ways.
= 31= (1+21+22+23+24)
= 31= (1+5+52)
Or, the number N can be 3×24 or 3×52. Or N can be 48 or 75.
So, more than one such number exists.
The sum of the factors of a number is 124. What is the number?a)Number...
The sum of factors of a number is 124. Let's find the possible numbers that satisfy this condition.
- Sum of factors of a number:
The sum of factors of a number is found by adding all the factors of that number.
- Possible numbers:
To find the possible numbers, we need to consider the factors of each number in the given ranges.
a) Number lies between 40 and 50:
- Factors of numbers in this range will be smaller than the given sum of 124.
- Therefore, there is no number in this range that satisfies the condition.
b) Number lies between 50 and 60:
- Factors of numbers in this range might satisfy the condition.
- For example, the factors of 60 are 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60. Their sum is 128.
c) Number lies between 60 and 80:
- Factors of numbers in this range might also satisfy the condition.
- For example, the factors of 72 are 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, 72. Their sum is 135.
d) More than one such number exists:
- As seen from the examples above, there are numbers in the ranges of 50-60 and 60-80 that satisfy the condition of having a sum of factors equal to 124.
- Therefore, the correct answer is option 'D'.
In conclusion, there are multiple numbers that could satisfy the condition of having a sum of factors equal to 124, and these numbers lie within the ranges of 50-60 and 60-80.