SOLUTION: Justin is making snowballs to build a fort on the winter break. Justin can build 15 snowballs in an hour but 2 snowballs melt every 15 minutes. How long will it take him to bui

Algebra ->  Numeric Fractions Calculators, Lesson and Practice -> SOLUTION: Justin is making snowballs to build a fort on the winter break. Justin can build 15 snowballs in an hour but 2 snowballs melt every 15 minutes. How long will it take him to bui      Log On


   

Question 490187: Justin is making snowballs to build a fort on the
winter break. Justin can build 15 snowballs in an
hour but 2 snowballs melt every 15 minutes. How
long will it take him to build 210 snowballs?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let y = total snowballs after x hours making them
+y++=+15x+-+2%2A%284x%29+
Note that +4x+ is the number of 15 minute periods in x hours
+y+=+15x+-+8x+
+y+=+7x+
+210+=+7x+
+x+=+30+
It will take him 30 hours
check:
+210+=+15%2A30+-+8%2A30+
+210+=+450+-+240+
+210+=+210+
OK