(Q). If N = p! + q! + r! is a two digit prime number. Then how many such value of N exist.
Solution:-
∴ 0! + 3! + 4! = 31      &  1! + 3! + 4! = 31
              ↓                       ↓
            prime                  prime
&Â no other cases
Hence 2 such values of N exists. Answer