x * (1-60/100) = 0.4x 0.4x + 60 = 240 0.4x = 240 - 60 0.4x = 180 x = 180/0.4 x = 450 The starting number is 450 What I did was decrease x “unknown starting number” by 10% giving 0.4x then I made a second equation by adding 60 and equaling to 240 then I simplified to find x.