Answer:
12
Step-by-step explanation:
1 ) Billy walks 15 miles every day to soccer practice and he had 5 practices last week.
We know that, 1 mile = 1760 yards
So, 15 miles = (15× 1760) yards = 26400 yards
Thus the total distance walked in 5 practices will be: 
2) Mark's current age is
years
So, his age was in 10 years ago 
Given that, his current age is 3 times his age 10 years ago.
So, the equation to represent this situation will be : 
Answer:
Answer is last alternative
scale factor (2)
We know that there are 21 buttons total. x is the number of small buttons and y is the number of large buttons.
Therefore, our first equation should be x+y = 21.
We know the small buttons sell for 3 dollars, meaning 3x represents how much is made from the small buttons. The larger buttons sell for 4 dollars, meaning 4y is how much is made from the large buttons.
We also know that the total of the buttons sold is 68 dollars. Therefore 3x + 4y = 68 is our second equation.
From this information, the answer is the first set.