Question
The average number of wafers in Box S, Box T and Box U is 42. Box S has 27 wafers. The number of wafers in Box T is twice the number of wafers in Box U. What is the number of wafers in Box U?
2 m

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The average number of wafers in Box S, Box T and Box U is 42. Box S has 27 wafers. The number of wafers in Box T is twice the number of wafers in Box U. What is the number of wafers in Box U?