After 40 minutes into a race, Flynn has run ⁵₁₁ of the route while Oscar has covered only ²₁₁ of the distance. Flynn runs at the same average speed throughout the race and Oscar’s average speed is 90 m/min slower than Flynn’s. If Oscar wants to finish the race at the same time as Flynn, by how many percent should he increase his average speed by for the remaining part of the race? Round off your answer to the nearest whole number.
Extra distance that Flynn ran more than Oscar in first 40 min
= 40 x 90
= 3600 m

Fraction of the entire distance that was covered by Flynn more than Oscar in the first 40 min
= ⁵₁₁ - ²₁₁
= ³₁₁

³₁₁ of the entire distance = 3600 m
¹₁₁ of the entire distance = 3600 ÷ 3 = 1200 m

Distance that Oscar ran in the first 40 min
= 2 x 1200
= 2400 m

Oscar's average speed
= 2400 ÷ 40
= 60 m/min

Flynn's average speed
= 60 + 90
= 150 m/min

Fraction of the journey that Flynn needed to run to complete the race
= 1 - ⁵₁₁
= ⁶₁₁

¹₁₁ of the entire distance = 1200 m
⁶₁₁ of the entire distance = 6 x 1200 = 7200 m

Duration that Flynn would take to complete
= 7200 ÷ 150
= 48 min

Fraction of the journey that Flynn needed to run to complete the race
= 1 - ²₁₁
= ⁹₁₁

⁹₁₁ of the entire distance = 9 x 1200 = 10800 m  

Speed that Oscar needs to take to complete distance at the same time as Flynn
= 10800 ÷ 48
= 225 m/min

Increase in Oscar's average speed
= 225 - 60
= 165 m/min

Percentage increase in Oscar's average speed
= ¹⁶⁵₆₀ x 100%
≈ 275%

Answer(s): 275%