Aptitude - Numbers - Discussion
Discussion Forum : Numbers - General Questions (Q.No. 75)
75.
Which of the following numbers will completely divide (325 + 326 + 327 + 328) ?
Answer: Option
Explanation:
(325 + 326 + 327 + 328) = 325 x (1 + 3 + 32 + 33) = 325 x 40
= 324 x 3 x 4 x 10
= (324 x 4 x 30), which is divisible by30.
Discussion:
23 comments Page 3 of 3.
Akash said:
4 years ago
3^25+3^26+3^27+3^28.
Here if we take a common among these, we get,
3^25*(1+3+3^2+3^3).
Now if we solve the bracket part which can be done easily, we get,
3^25 * 40.
Now factoring in the term 40, and 3^24 * 3=3^25 do not get confused, the equation looks likes,
3^24 * 3 * 4 * 10,
3^24 * 4 * 30.
Here the term 30 will completely divide the equation.
Here if we take a common among these, we get,
3^25*(1+3+3^2+3^3).
Now if we solve the bracket part which can be done easily, we get,
3^25 * 40.
Now factoring in the term 40, and 3^24 * 3=3^25 do not get confused, the equation looks likes,
3^24 * 3 * 4 * 10,
3^24 * 4 * 30.
Here the term 30 will completely divide the equation.
(2)
Riya said:
3 years ago
I didn't understand how 40 came? Anyone, please explain.
(1)
Addagiri lakshmipriyanka said:
2 years ago
(3^25 + 3^26 + 3^27 + 3^28) = 3^25 x (1 + 3 + 32 + 33) = 3^25 x 40.
3^24 x 3 x 40.
3^24 x 3 x 4 x 10.
Sum = 120 which is divisible by 30.
So, option D is correct.
3^24 x 3 x 40.
3^24 x 3 x 4 x 10.
Sum = 120 which is divisible by 30.
So, option D is correct.
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