If you are evaluating the answer is -41
Answer:
1.46
Step-by-step explanation:
First find the the mean score before he made a 90.

Now add the score of 90 and calculate.

Subtract the two scores.

His mean test score increased by 1.46.
equation for first figure=2x+y=2
equation for second figure= 4x-y=8
(use formula x/a+y/b=1)
where, a=x component and b= y component..
Answer:
The answer should D) I, II, and III