Question 1057469
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An hourglass is turned over with the top part filled with sand. After 3 minutes, there are 855 mL of sand in the top half. 
After 10 minutes, there are 750 mL of sand in the top half. What is the y-intercept?
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The rate is {{{(855-750)/(10-3)}}} = {{{105/7}}} = 15 mL of sand per minute.


Now add 3*15 mL to 855 mL. You will get 900 mL.


It is your answer.


Now you think why.
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