The lowest amount of money she can spend buying the same amount of cups and plates is..
$43.00
To figure this out, we must find the least common multiple (LCM) of 12 and 10. The LCM of 12 and 10 is 60. After we have figured that out, we must figure out how much money it costs for 60 of each product. So in order to do this, we must first find how many packs she purchased of each product. Once we have found that she purchased 5 packs of each, we must do the math and figure out how much money it cost for 5 packs of each. For 5 packs of cups, it costed her $18, because 3 x 5 = 18. For 5 packs of plates, it costed her $25, because 5 x 5 = 25. We must then add together those two numbers to find our final answer. When adding 18 and 25, we get the sum of 43. That means she spent $43 dollars in total.
Hope this helps! :)
