Question

nisha secured 73,86,78 and 75 marks in four tests what is the least number of marks she can secure in her next test, if she has to have mean score of 80 marks in five tests? pls answer in detail

Answer 1

lets take the marks as x .....as given ,mean is 80 .....number of observations are 5 ....so according to the mean formula ......
$(73 + 86 + 78 + 75 + x) \div 5 = 80$
so answer will be 88 marks