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What is the greatest integer that is a sum of four different prime numbers, each less than 30?

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Re: What is the greatest integer that is a sum of four different prime numbers, each less than 30?

by Nirav Umaretiya » Sat Sep 12, 2020 11:09 pm
To solve this PS, the best way is to bring everything you know on the notepad.
So you need to use the Prime Numbers less than 30.

Primes
01 to 10: 2, 3, 5. 7
11to 20: 11, 13, 17, 19
21 to 30: 23, 29

Now you need to use 4 distinct primes and you have to create the largest possible integer.
So take 29 + 23 + 19 +17 = 88

So the correct answer is B

takeaway
1) we are not considering the negative primes in this question because using any negative number will be reducing the sum, and we need the largest possible sum.
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Re: What is the greatest integer that is a sum of four different prime numbers, each less than 30?

by deloitte247 » Sun Sep 13, 2020 12:12 am
For the sum to be maximum, the prime numbers must be the maximum possible numbers.
So given that we are looking for 2 different prime numbers < 50, the maximum prime numbers are 47 and 43.
Therefore, 47 + 43 = 90

Answer = option B
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