Question

Nisha secured 73 ,86 ,78 and 75 marks in four test what is the least number of marks she can secure in next test if she has to have a mean score of 80 in 5 test​

Answer 1

let the fifth marks be x then

$\frac{73 + 86 + 78 + 75 + x}{5} = 80$

$\frac{312 + x}{5} = 80$

$312 + x = 400$

$x = 400 - 312$

$x = 88$