Question 510906
Let's find the sum of her first seven scores, we'll call this y:
{{{y/7 = 83}}} Multiply both sides by 7.
{{{y = 581}}} Now you want the average of eight test scores to be 90. Lets call the score of the eighth test x, so...
{{{(581+x)/8 = 90}}} Multiply both sides by 8.
{{{581+x = 720}}} Subtract 581 from both sides.
{{{x = 139}}}
Flora will need to score 139% on test eight. Not possible!