math help percentages?

Question

13: Eighty percent of the students in a school, or 680 of them, contributed to the school's social fund. How many students are there in the school?
770
820
850
895


14: The prices of all meats increased 5% per pound. In what sense were the increases unequal?
percent increase
types of items increased
price increase
number of items increased


15: At the end of the first year a baby should weigh about 300% of its weight at birth. If a baby weighs 8 1/2 lb. at birth, what should it weigh at one year?
24 3/4 lbs
25 lbs
24 1/2 lbs
25 1/2 lbs


16: When asked how a charity campaign was going, the secretary said that they had raised $12,000 and had 20% more to go to meet the goal. What was the goal?
15,000
14,500
15,500
17,000


17: On an airplane a passenger may carry 40 pounds of baggage free. For each pound over 40 pounds, the passenger must pay 1/2 % of the total fare. If the baggage weighs 54 pounds and the fare is $35, what is the extra charge?
$3.10
$2.45
$2.20
$3.00

Answer 1

13. Take 680/.8. This is actually algebra. In other words X * .8 = 680. Change the formula by dividing .8 and X=680/.8 or 850.

14. Logic question, asking what was the set of items increased. If I am reading the answers correctly, it is types of items increased, since only meat was up 5% not milk for example

15. Percent question. 300% equal a multiple of 3 pounds. So 8.5 pounds at birth x 3 equals 25.5 pounds (25 1/2)

16. This is like 14 but a little different. Goal equals X. X*.8=12,000. So factor the .8 and arrive at 12,000/.8 and that equals 15,00000

17. Multiple calculations. First, how much is the bag overweight? It is 14 pounds (54-40.) Second, what is decimal for a half a percent, .005. Third, the formula for the surcharge is (35*.005) * 14. In words, Price x the surcharge (for one pound) x the pounds over. This equals $2.45

Reply with questions if any

Answer 2

Here's some help. I'm not going to give you the answers though.

13: Eighty percent of the students in a school, or 680 of them, contributed to the school's social fund. How many students are there in the school?

680 = 80/100 * number of students
68000 = 80 * number of students

14: The prices of all meats increased 5% per pound. In what sense were the increases unequal?
Mark which ones you know are incorrect.

percent increase - NO, they all increased 5% per pound
types of items increased
price increase
number of items increased

15: At the end of the first year a baby should weigh about 300% of its weight at birth. If a baby weighs 8 1/2 lb. at birth, what should it weigh at one year?
300% = 3x
8 1/2 * 3 = ...

16: When asked how a charity campaign was going, the secretary said that they had raised $12,000 and had 20% more to go to meet the goal. What was the goal?
$12,000 = 80% of goal
Find out what 100% is

17: On an airplane a passenger may carry 40 pounds of baggage free. For each pound over 40 pounds, the passenger must pay 1/2 % of the total fare. If the baggage weighs 54 pounds and the fare is $35, what is the extra charge?

54 pounds - 40 pounds = 14 pounds
$35 = total fare. For each pound over 40 (14), passenger must pay 1/2% of $35.
So 14 * (17.5/100) =

Answer 3

OK, get your calculator out and let's go to work

Question 13

You have 680 students but you need to find out how many students total. Use division in this problem. Divide 680 by your percentage 80%

Question 14

If you are going to increase the price of meats what is going to make it different. Now think here. Are all meats the same?

Question 15

Here you use multiplication. Baby's weight by the percent.

Question 16

Here you will divide by the unknown percentage. What part of 100% is 20%? Take your answer and divide the $12000 by it.

Question 17

Subtract th 54 from 40 because you know the first 40 pounds are free. Now take the answer and take half of it times your $35 fare.

Good luck :-)

Answer 4

13. 850
14. price increase
15. 25 1/2 lbs.
16. $15,000
17. $2.45