If × stands for - , ÷ stands for + , + stands for ÷ and - stands for ×, then 15 - 5 ÷ 5 × 20 + 10 is equal to

12 6 72 78

78

15 - 5 ÷ 5 × 20 + 10 = 15 × 5+ 5 - \(\frac{20}{10}\) = 75 + 5 - \(\frac{20}{10}\) = 75 + 5 - 2 = 80 - 2 = 78