Answer:
20
Step-by-step explanation:




30 apples bc 5x6 (5 six times) =30
ratio of adults to students can be written as a fraction
adult tickets / student tickets
140/210 can be simplified to 14/21
14/21 can be simplifed to 2/3
12+6x was subtracted from the left but only 12 was subtracted from the right.
6x and 6 are not equal unless x=1
X=-11/15