x - y = - 11 .............( 1 )
y + 7 = - 2x ...............( 2 )
from equation ( 1 )
x - y = - 11
x = -11 + y ...........( 3)
putting x in equation ( 2 )
y + 7 = - 2 x
y + 7 = -2 ( -11 + y ) y + 7 = 22 - 2 y y + 2 y =22 - 7
3 y = 15 y = 15 / 3
putting value of y in equation 3
x = -11+ ( 13 /5 ) x = -33 /3 + 15 / 3 ( l.c.m)
x = -17 / 5
check
x = -11 + y
- 17 / 5 = -11 + 13 / 5
-17 /5 = -17 / 5
Answer:
according to basic proportionality theorem
Answer:
9.5
Step-by-step explanation:
The average score of all the students in both classes is 84.
<h3>How to calculate the average?</h3>
The class with 30 students had an average score of 80 on a test. The total score will be:
= 30 × 80
= 2400
A class with 20 students had an average score of 90 on the same test. The total score will be:
= 20 × 90
= 1800
Total scores = 2400 + 1800 = 4200
Number of students = 20 + 30 = 50
The average score will be:
= Total score / Total students
= 4200 / 50
= 84
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Answer:
Step-by-step explanation:
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