70 If they wanted you to cut 30 in half, they would have said "Divide 30 by 2", "Multiply 30 by 1/2" or "Cut 30 in half" (or something along those lines)
So the answer would be 70. If the problem would be divide 30 by 2 and add 10, the answer would be 25. But here it says divide by half that is 0.5, so that becomes double of 30 = 60. And 60+10=70
You might be tempted to answer 25 but the correct answer is 70. When you divide 30 by 1/2, the result is 60. (30/1/2 = 30 x 2 = 60) Adding 10 to this we get; 60 + 10 = 70 Answer = 70