The octal number 347 is equivalent to:  

The octal number 347 can be represented as:

3×82+4×81+7×80.

Now, let’s calculate:

3×64+4×8+7×1

=192+32+7

=231.

Therefore, the decimal equivalent of the octal number 347 is 23110.

To convert the decimal number 231 to hexadecimal, we can use the repeated division method. Here are the steps:

231÷16=14 remainder 7.

Now, divide the quotient (14) by 16:

14÷16=0 remainder 14.

The remainder 14 represents the most significant hexadecimal digit, which is E in hexadecimal.

Therefore, the decimal number 231 is equivalent to the hexadecimal number 

E716.