How do i convert 0.4 into a fraction explain

Write the converse of the following statement: if the trees have no leaves, then it is fall. if the trees have no leaves, then it is fall. the trees have no leaves, therefore it is fall. it is fall since the trees have no leaves. if it is fall, then the trees have no leaves.

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

Suppose that the price p, in dollars, and the number of sales, x, of a certain item follow the equation 4 p plus 4 x plus 2 pxequals56. suppose also that p and x are both functions of time, measured in days. find the rate at which x is changing when xequals2, pequals6, and startfraction dp over dt endfraction equals1.5.