Question

Sara got a 70%, 64%, and 83% on her first three tests. What must she get on her 4th test if she wants to get a final average of 75%?

Show your work, please.

Answer 1

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 2

Answer: she must score 83% on her 4th test if she wants to get a final average of 75%

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%