Trigonometry · Medium problem

A bicycle has a front chainring of radius $10$ cm connected by a chain to a rear sprocket of radius $4$ cm; the rear sprocket is fixed to the rear wheel of radius $34$ cm. The rider pedals the chainring at $80$ rev/min. Find the bicycle's speed in km/h. (The chain gives the two sprockets equal linear rim speed; the sprocket and wheel share an axle.) Round to 1 decimal place (an exact answer is also accepted).