Question

Here is bob's test score math 65 arts 86 science 84 social studies 78 if his average score is 80 ,how many marks did he make in gramma

Answers

Bosnian
x1 = score math = 65

x2 = score arts = 86

x3 = score science = 84

x4 = score social studies = 78

x5 = score grammar


average = ( x1 + x2 + x3 + x4 + x5 ) / 5 = 80


( 65 + 86 + 84 + 78 + x5 ) / 5 = 80

( 313 + x5 ) / 5 = 80 Multiply both sides by 5

313 + x5 = 80 * 5

313 + x5 = 400 Subtract 313 to both sides

313 + x5 - 313 = 400 - 313

x5 = 87

score grammar = 87


Proof :

( x1 + x2 + x3 + x4 + x5 ) / 5 =

( 65 + 86 + 84 + 78 + 87 ) / 5 =

400 / 5 = 80










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