Jen Butler has been pricing Speed-Pass train fares for a group trip to New York. Three adults and four children must pay $\$106$. Two adults and three children must pay $\$75$. Find the price of the adult's ticket and the price of a child's ticket.
+36916 3a + 4c =106
2a + 3c = 75 multiply this eq by - 1.5 abd add to top equation to get :
-.5 c = -6.5
c = $ 13
2a + 3(13) = 75
a = $ 18
