Rename 0.200 using other place values

Im so bad at fractions they are not my best math thing to work on

Aliter of water contains about 3.35 x 10^25 molecules. a certain river discharges about 2.9x 10^8 l of water every second. about how many molecules does the river discharge every minute? write your answer in scientific notation

Of the total number of spectators at a circus show, 1/4 are men. 2/5 of the remaining number of spectators are women. there are 132 women at the circus show. how many children are at the circus show?