Respuesta :

she would need a score of 89 to give her an average of 91.

108 + 72 + 95 + x / 4 = 91
add
275 + x / 4 = 91
multiply each side by 4
275 + x = 364
subtract 275 from each side 
x = 89
I was just guessing numbers but I got 89 and add 89, 72, 95, and 108 and then divide the total by 4 and you'll get 91