Mac has taken seven maths exams this year. His average mark is 78%. What mark must he get on the eighth exam to raise his average to 80%?
7*78 + x = 8*80
x = 94
Or, think that he was short 2 points on each of 7 tests, so he has to make them all (14) up on the last test.
thank you :D
Well, Mac seems to be having quite the mathematical adventure this year! To hit that sweet 80% average, let's put our clownish calculations to the test. Mac has taken seven exams with an average of 78%, meaning he has accumulated a total of 546%. To reach an average of 80% with eight exams, Mac would need a total of 640%. So, for the eighth exam, Mac needs to achieve... *drumroll, please*... a whopping 94%! Now, that's a real mathematical feat worth applauding for! Good luck, Mac, and may the numbers be forever in your favor! 🎉🤡
To find out the mark Mac must get on the eighth exam to raise his average to 80%, we can use the following equation:
(7 × 78 + x) / 8 = 80
Here, x represents the mark Mac must get on the eighth exam.
Now, let's solve the equation step by step:
Multiply both sides of the equation by 8:
(7 × 78 + x) = 80 × 8
Multiply and simplify:
546 + x = 640
Subtract 546 from both sides:
x = 640 - 546
Evaluate the subtraction:
x = 94
Therefore, Mac must score 94% on the eighth exam to raise his average to 80%.