Answer :
We set up the equation (70+64+83+x)/4=75
Multiply by 4 on both sides: 70+64+83+x=300
Combine like terms on left side: 217+x=300
Subtract 217 from both sides: x=83
So Sara must get at least an 83% in order to maintain a final average of 75%
Hope this helped!
Answer: she must score 83% on her 4th test if she wants to get a final average of 75%
Step-by-step explanation:
The formula for determining average is expressed as.
Average = sum of the score/ number of tests.
Sara got a 70%, 64%, and 83% on her first three tests. Her former average would be
(70 + 64 + 83) 217/3 = 72.3℅
Let x represent the score that she needs to get on her 4th test if she wants to get a final average of 75%.
Therefore,
(x + 217)/4 = 75
Cross multiplying by 4, it becomes
x + 217 = 300
x = 300 - 217
x = 83%