Hello there!
What is 25% of 400?

= 
= 100
Thus,
25% of 400 is 100
What is 5% of 20?
Well, we just need to follow the previous steps.

= 
Thus,
5% of 20 is 1
I hope this answer helps. Let me know if you have additional questions about the answer. As always, it is my pleasure helping student like you.
Answer:
1 * 10^12
Step-by-step explanation:
Scientific notation is a representation of a large number in a short form. The answer, 1*10^12 (read as ten to the twelfth power) essentially says that the number when expanded is 1 with 12 zeros appended to it. If you did a number like 7 trillion you would have 7 * 10^12.
Same thing can be applied for 1,000,000 (one million).
1 * 10^6 because one million has 6 zeros appended to it.
The first thing you should do is calculate how many pounds of cheese a hamburger has
1 hamburger = 1/4 pound of cheese.
Then, you can make a rule of three to know how many pounds of cheese were sold:
1 ---> 1/4
310 ---> x
Clearing x we have:
x = ((310) / (1)) * (1/4) = 77.5
Answer
they sell last saturday 77.5 pounds of cheese
No, because the 9 pounds would cost 22.5, and that is 5 cents more than he has