The three scores are 86, 74, and an unknown score x. The average (i.e. the sum divided by how many there are) is 80, so we have
Multiply both sides by 3 and you get
Subtract 160 from both sides to get
Note: you could solve this exercise very quickly if you notice that the two numbers, 86 and 74, are symmetrical with respect to 80, which is the average. So, the third number must be the average.
Answer:
n=3
Step-by-step explanation:
20+20+20 length +width+ height
20×3
Using substitution:
first you have to express one variable in terms of the other, in this we can express y in terms of x:
Since both expressions are equal to y, you have to equal both expressions like this:
Now you can solve the equation:
Knowing x=10, you can use any of the expressions we found before to find y. In this case I'm going to use y= -x+9 because it's simpler but boy should give you the same result
So, the answer is x=10 and y=-1
10:10
11:11
Those are 2 ratios that are correct
