Let temperature of tuesday = a, temperature of wednesday = b and temperature of thursday = c Sum of temperatures of tuesday to thursday = 38 × 3 =114 ∴ a+b+c=114 Sum of temperatures of wednesday to friday = 37 × 3 =111 b + c + friday=111 ∴ Temperature of friday = 39 ∴ b + c + 39 =111 ∴ b + c =(111 – 39) =72 ∴ a + b + c = 114 a + 72 = 114 ∴ a = (114 – 72) = 42 ∴ Temperature on tuesday = 42°C