<span>valid. She used a representative sample
</span>because she correctly found the average and 18,000 is a reasonable number to get for a the problem
Answer:
5
Step-by-step explanation:
see explanation, use tangent property to solve question
Answer:

Step-by-step explanation:
Total Volume of Water = 
Volume drunk by James =
Volume drunk by Simon =
Volume drunk by Matthew = 
Volume drunk by Gilbert =
Total Volume Drunk (i.e. The Sum) = 
Volume of water Left = Total Volume of Water-Total Volume Drunk
= 
So the total amount of marbles is: 20+12=32
there are 20 pink marbles
20/32 = 10/16 = 5/8 (simplified)