Physics class had a mean = 60 and standard deviation = 6.9
History class had a mean = 70 and standard deviation =10.7
Simon had the same test score on both tests a day had the same z-score on each test.
What was Simon's test score?
we know that
The z-score is equal to
z=(x-mean)/s
where
x is the test score
s is the standard deviation
substitute the given values
Physics class
z=(x-60)/6.9
History class
z=(x-70)/10.7
equate both equations
(x-60)/6.9=(x-70)/10.7
solve for x
10.7(x-60)=6.9(x-70)
10.7x-642=6.9x-483
10.7x-6.9x=642-483
3.8x=159
x=41.84
therefore
the test score is 41.84