Or, 300x = 2400,
x = 8"

Suppose the cone pulley on the counter shaft runs 600 R.P.M.; a lathe
spindle runs 2200 R.P.M., when connected with the small cone pulley
which has a diameter of 3". The large cone pulley has then a diameter of
11".

600 : 2200 :: 3 : x
Or, 600x = 6600;
x = 11"


RULES FOR FINDING THE SPEEDS AND SIZES OF PULLEYS

1. To find the diameter of the driving pulley:

Multiply the diameter of the driven by the number of revolutions it
should make and divide the product by the number of revolutions of the
driver. (20 x 300 = 6000; 6000 ÷ 1500 = 4"--diameter of motor pulley.)

2. To find the diameter of the driven pulley:

Multiply the diameter of the driver by its number of revolutions and
divide the product by the number of revolutions of the driven. (4 x 1500
= 6000; 6000 ÷ 300 = 20"--diameter of the driven pulley.)

3. To find the number of revolutions of the driven pulley:

Multiply the diameter of the driver by its number of revolutions and