A car operates at maximum economy, gas-wise, at speeds between 25 and 35 miles per hour.
-4
First four countries to have television: England, the U.S., the U.S.S.R., and Brazil.
47
The oil used by jewelers to lubricate clocks and watches costs about $3,000 a gallon.
41
Castor oil is used as a lubricant in jet planes.
-5
In the early 1960's, Porsche commercially manufactured farm tractors.
24
An airplane mechanic invented Slinky while he was playing with engine parts and realized the possible secondary use for the springs.
12
More than a billion transistors are manufactured every second.
-25