Personal Comment: Try several ways of solving this.

Racecar Enigma!

What we know: A race driver drove around a 6-mile track at 140 mph for 3 miles. Then 168 for 1½ miles. Then 210 for the last 1½ miles.

Enigma: What is his average speed for the whole 6 miles?

Solution: 160 mph. The secret lies in converting the units to miles per minutes and using fractions instead of decimals to avoid rounding errors.

See who got this right

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