35, if no brackets then division and multiplication is before the addition, so 5+25+5. PS I can't even work out how 75 is a possible answer, no matter what order you do it in!

35 .... (there is no need for brackets - multiplication has to be done 1st) but most people would disgree, I have even seen wrong answers like these is different tests :/

PEMA! Parenthesis, Exponents, Multiplication (Division is implied as its just the converse) and then addition (ditto on subtraction). I remember it as the sexy PETA ads.