D.) 2.13 < 2.3 is correct. This is stating that 2.3 is greater than 2.13, which is true. In the other possible answers, for example 4.15 > 4.51, this would be false because 4.15 is not greater than 4.51. The open end of the greater than or less than sign will always point to the bigger number.
Answer: Choice A
The second fraction should not have been multiplied by 9
This is because 1/9 already has the LCD in the denominator. LCD stands for lowest common denominator.
The first fraction 2/3 does not have 9 in the denominator, which is why they multiplied top and bottom by 3
2/3 = (2*3)/(3*3) = 6/9
After each fraction has the same denominator (9), you can add the numerators to place over the LCD like so
6/9 + 1/9 = (6+1)/9 = 7/9
This means,
2/3 + 1/9 = 6/9+1/9 = 7/9
The larger number is 120 and the smaller number is 80
Well, suppose she gets x points in 7th round. Then she wants mean to be 75, meaning
(72+79+74+76+76+75+x)/7=75
Can you find x from here?