October 16, 2023
October 16, 2023
October 16, 2023
###### UGC NET CS 2015 Jun- paper-2
October 16, 2023
 Question 1
How many strings of 5 digits have the property that the sum of their digits is 7?
 A 66 B 330 C 495 D 99
Question 1 Explanation:
→ From the given question, there should be string with 5 digits and sum of that digits should be 7
→ There is no specification about positive,negative digits and also repetition of digits.
→ We are assuming the positive digits which is greater than or equal to 0.
→ The starting digit of the string should not be zero. We will also consider the repetition of digits.
→ Example of such strings are 70000,61000,60100,60010..,
→ The possible number of strings are C((n+r-1),(r-1))
→ From the given data n=7,r=5 then We have to fine C(11,4) which is equal to 330
Question 1 Explanation:
→ From the given question, there should be string with 5 digits and sum of that digits should be 7
→ There is no specification about positive,negative digits and also repetition of digits.
→ We are assuming the positive digits which is greater than or equal to 0.
→ The starting digit of the string should not be zero. We will also consider the repetition of digits.
→ Example of such strings are 70000,61000,60100,60010..,
→ The possible number of strings are C((n+r-1),(r-1))
→ From the given data n=7,r=5 then We have to fine C(11,4) which is equal to 330