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This problem trains for: SAT-I, AMC-8, GMAT.

Tarzan swam 5 times in a 100 ft. freestyle race and achieved an average time of 53 seconds. After this, he was sent a new type of swimsuit which enabled him to lower his average time by 3% over the following 3 races. What average time did he achieve over the whole tournament?

(character from Edgar Rice Burroughs "Tarzan of the Apes")

The total time for the first 5 races was:

equation

The average time for the following 3 races was:

equation

The total time for the following 3 races was:

equation

The average time for the whole set of races:

equation