If his best time is x, and the best time is smaller, then (1+1/3)*x=his second best time. If x+4=his second best time (since his second best time is 4 seconds slower), then (1+1/3)*x=x+4. Multiplying it out, we get (3/3+1/3)*x=x+4 =4x/3=x+4. Subtracting x from both sides, we get 4x/3-3x/3=x/3=4. Multiplying both sides by 3, we get x=12=his best time
Answer is 175 To start you need to work backwards from the mean so do 158*4 to give you the total of the revenue then simply minus what was given to get 175 Hope this helped