Answer:
4, 1, 6.
See explanation
Step-by-step explanation:
You are given the equation

First subtract
from both sides:

and multiply the equation by -1:

Now multiply (1) by 2:

At last, divide by 

Here we can use fact than we can multiply fraction by inverse of fraction instead of dividing it.
Inverse of 1/3 is 3/1
Lets multiply it

- its our result
If Heather can do 2 in 10 minutes, then that means that she can do 12 in 1 hour. If Joel can do 3 in 15 minutes, then it means that he can do 12 in 1 hour. Add the number of problems they can do total and that will go between 30 and 50. It is just "less than", not "less than or equal to" because you want to know when the total number goes between the numbers.
Therefore, the correct answer must be <span>30 < 24x + 5 < 50.</span>