While making a sandcastle and moat on the beach, Glenda fills 3 pails with sand and 1 pail with water. The pails are of equal size. What fractional part of the pails contains sand?

Here's link to the аnswer:

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not only in mathematics, scientific proof also are required in the other field of science. also maths proofs are of particular structure, containing steps and logics. so proving is like doing science, it is science. that's why it is important to prove. 

an inaccurate proof leads to errors, or stating results that are not accurate.  which wil mess the probelm up you dont want this

a is the right answer