Question 639527

current grades in Algebra I are {{{74}}}, {{{88}}}, {{{87}}} and {{{83}}}

 What grade (let' it be {{{x}}}) do you need on the next test to raise your average to at least {{{85}}}?

first you need to know that an average is a sum of all grades divided by number of grades

so, you have

{{{(74+88+87+83+x)/5=85}}}

{{{(332+x)/5=85}}}

{{{332+x=85*5}}}

{{{332+x=425}}}

{{{x=425-332}}}

{{{highlight(x=93)}}}


check:

previous average grade was:{{{(74+88+87+83)/4=83}}}

if you get {{{93}}}on the next test, average grade will be

{{{(74+88+87+83+93)/5=425/5 =85}}}