Question

The melarks Scored by a student by a stutent in five subjects are 80 ,75,66, ,51,and 91 how much should he score in the 6th subject to make his average score 75







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Answer 1

Let "n" represent  the number we are looking

Equation:

$(80+75+66+51+91+n)/6=75$

Solve:

$(80+75+66+51+91+n)/6=75\\6(80+75+66+51+91+n)/6=75(6)\\80+75+66+51+91+n = 450\\363 + n=450\\363 - 363 + n = 450 - 363\\n=87$

Answer:

He needs to score 87 in the 6th subject to make his average score 75.

Hope you mark this as brainiest ;)