Easy, she needs

but only has

So, take,

=
=

So, she needs to fill it 3 times.
Answer:
Its answer number 2 for sure.
Answer:
, ](https://tex.z-dn.net/?f=%5B16%20%2B%20%28-18%29%5D%28-4%29)
Step-by-step explanation:
Given: The low temperature on Monday was 16°F. The low temperature on Tuesday was 18°F cooler. The low temperature on Wednesday was –4 times Tuesday’s temperature.
To find: expression that can be used to describe the low temperature on Wednesday
Solution:
Temperature on Monday = 16°F
So,
Temperature on Tuesday = 
Temperature on Wednesday = 
So, expression
can be used to describe the low temperature on Wednesday.
Also,
\,\,\left \{\because (a-b)=\left [ a+(-b) \right ] \right \}](https://tex.z-dn.net/?f=%2816-18%29%28-4%29%3D%5B16%20%2B%20%28-18%29%5D%28-4%29%5C%2C%5C%2C%5Cleft%20%5C%7B%5Cbecause%20%20%28a-b%29%3D%5Cleft%20%5B%20a%2B%28-b%29%20%5Cright%20%5D%20%5Cright%20%5C%7D)
So, expression
also represent temperature on Wednesday.
There are three groups of people: 25 years old and younger, between 25 to 50, and 50 years old and older. Their fractions must equal to 1 because these three together form the whole.
1 = 1/3 + 2/7 + x
where x is the fraction for people ages 25 to 50 years old
x = 8/21
So, the actual number of people ages 25 to 50 years old is:
84(8/21) = 32 people