The average cost of 7 pastries is $10.50. If the first six pastries cost $15.50, $11, $9.75, $11.25, $9.50 and $10.50, what is the cost of the last pastry

Question

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Answer 1

(15.5+11+9.75 +11.25+ 9.5 + 10.5 + X)/7 = 10.5

solve for X

(67.5 + X)/7= (10.5)

67.5 + X = 7(10.5)

X = 73.5 - 67.5

X = $6 = cost of the 7th pastry