Final answer:
To get an average score of 90 in four subjects, Ami needs to score a combined total of 190 marks in Chemistry and Biology after having scored 75 in Maths and 95 in Physics.
Step-by-step explanation:
Ami is aiming to achieve an average score of 90 across four subjects, with each subject having a maximum score of 100 marks. To determine the scores that she needs to achieve in Chemistry and Biology (the remaining two subjects), we begin by calculating the total marks she requires for the desired average.
Since the desired average is 90, for four subjects, the total marks needed would be: 90 marks/subject × 4 subjects = 360 marks.
Ami scored 75 in Maths and 95 in Physics, which sums up to: 75 + 95 = 170 marks.
To find out the remaining marks she needs, we subtract the marks she has already scored from the total marks needed for the average:
360 marks (total needed) - 170 marks (already scored) = 190 marks (needed for Chemistry and Biology).
Therefore, to ensure that she gets the desired average score of 90, she would need to score a combined total of 190 marks in Chemistry and Biology. This could be achieved by, for example, scoring 95 in both subjects or any other combination that adds up to 190.