A bag contains yellow, green, blue, and white marbles. The ratio of yellow, green, blue, and white marbles is 1:2:3:4. If the bag contains 180 marbles, then how many blue marbles are there?
\(( {\color{goldenrod}1}+{ \color{green}2}+{ \color{blue}3}+{ \color{Gray}4})n=180\\ 10n=180\\ n=18\\ There\ are\ {\color{blue}18\cdot 3=54}\ blue\ balls\ in\ the\ bag.\)
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