20. In a factory the ratio of number of defective bolts produced to the number of good bulbs is 1 : 10.
In one hour the factory produced 330 bolts. Find
the number of defective bulbs produced by the
factory in an hour​

Acertain volume of water contains 100000 hydrogen atoms and 50,000 oxygen atoms how many hydrogen atoms are in a volume of water containing 4 million oxygen atoms

This is a map of the mars exploration rover opportunity predicted landing site on mars. the scale is 1cm : 9.4km. what are the approximate measures of the actual length and width of the ellipse? i mostly need to know how to set it up : )

What is the circumference of the pie