Question 11 - Figure it out - Page 114, 115 - Chapter 5 Class 6 - Prime Time (Ganita Prakash)

Transcript

Question 11 How many three-digit prime numbers can you make using each of 2, 4 and 5 once?All possible 3 digit numbers using 2, 4 and 5 once are Ending with 2 – 452, 542 Ending with 4 – 254, 524 Ending with 5 – 245, 425 Now, we note that Numbers ending with 2 and 4 are divisible by 2 Numbers ending with 5 are divisible by 5 Thus, all of these numbers have either 2 or 5 as a factor, which means it has more than 2 factors.. ∴ There is 0 three-digit prime numbers that can be made.