X+y=155. Y= -x+155
1.50x +4(-x+155)= 520
1.50x-4x+620=520
-2.5x =-100
X= 40. Y=110
43 units
count all the square boxes. count the boxes covering more than half and leave the boxes covering less than half. I hope it's correct.
Answer:
A, B and C
Step-by-step explanation:
A. Adding another researcher to provide ratings will make the study less biased.
B. A quiz or exam will show which students have a better understanding of the math material. Better quiz or exam results show that the site is more effective for a student with or without the supplemental instruction.
C. Having a greater sample size is better because a greater scope of students is covered. Different students have different abilities and learning preferences.