In a class of 30 students, 17 students study Chinese, and r students study Japanese. Every student studies either Chinese, Japanese, or both. How many students study both Chinese and Japanese?
(1) r = 14
(2) Thirteen students take only Japanese.
1.so we have C=17 and r=14. so we can see the overlap here. SUFF
2. so we know 13 take only japanese so we have 17 students left who study chinese BUT we dont know the dual language students so INSUFF
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