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

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.

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