Help me. Math?

Question

1: Be careful to answer the right question! Sometimes you solve for one traveler's time, then need to find the other traveler's time. Ask yourself each time: "what is the question asking for?"
Two jets leave an airport at the same time in opposite directions. The first jet is traveling at three hundred forty one mph and the other at three hundred thirty two mph. How long will it take for the jets to be 1,616 miles apart? Round your answer to the tenths place.

Hint: you are given a total distance. Therefore, jet 1's distance expression plus jet 2's distance expression equals the total distance.






179.3 hours
2.4 hours
6.2 hours


2: Alexis left Miami and drove at a speed of 20 kph. Thomas left 3 hours later and drove at a speed of 30 kph. How long will it take Thomas to catch up to Alexis?


Hint: since they both go the same distance, we can set their distance expressions equal for the equation. Get the distance expressions for each by using the D = RT formula.




9 hours
7.5 hours
6 hours


3: Savannah left Miami and drove at a speed of 47 mph. Timothy left 2 hours later and drove at a speed of 58 mph. How long will it take Timothy to catch up with Savannah?
Hint: since they both go the same distance, we can set their distance expressions equal for the equation.





8.55 hours
10.55 hours
7.5 hours


4: Two jets leave an airport at the same time in opposite directions. The first jet is traveling at three hundred twenty-three mph and the other at two hundred mph. How long will it take for the jets to be 2,371 miles apart?
Hint: you are given a total distance. Therefore, jet 1's distance expression plus jet 2's distance expression equals the total distance.





4.53 hours
2.37 hours
123 hours


5: Caleb left New York and drove at a speed of 15 kph. Ryan left 3 hours later and drove at a speed of 20 kph. How long will it take Ryan to catch up with Caleb? ?
Hint: since they both go the same distance, we can set their distance expressions equal for the equation.





12 hours
9 hours
6 hours


6: Alexander left Miami and drove at a speed of 46 mph. Thomas left 1 hour later and drove at a speed of 60 mph. How long will it take Thomas to catch up with Alexander?
Hint: since they both go the same distance, we can set their distance expressions equal for the equation.





4.29 hours
3.29 hours
5.29 hours


7: Kyle left Miami and drove at a speed of 46 mph. Eric left 1 hour and 45 minutes later (which is 1.75 hours) and drove at a speed of 62 mph. How long will it take Eric to catch up with Kyle?


Hint: since they both go the same distance, we can set their distance expressions equal for the equation.




6.78 hours
3.2 hours
5.03 hours


8: Morgan and Thomas left Seattle at three in the afternoon, traveling in opposite directions. At six p.m., they were one hundred eighty-nine kilometers apart. If Thomas' rate of speed is two times that of Morgan's, what is Morgan's speed?


Hint: you are given a total distance. Therefore, Morgan's distance expression plus Thomas's distance expression equals the total distance.




17 kph
24 kph
21 kph


9: Megan left Seattle and traveled at a rate of thirty-one kph more than two times the speed of Isaac, who left at the same time but in the opposite direction. After 1.22 hours, they were 133 kilometers apart. What was Megan's speed?

Hint: you are given a total distance. Therefore, Megan's distance expression plus Isaac's distance expression equals the total distance. This answer depends on how you rounded throughout; select the closest or ask for help.





83 kph
23 kph
26 kph


10: Jacob left Seattle and drove his car at thirty-five mph. Caleb wanted to catch up with Jacob but left from the same point at 4:04, which was 1.37 hours later. Caleb traveled at a speed that was sixteen mph more than Jacob did. At what time will Caleb catch up with Jacob?
Hint: express Jocob's time in hours first. Then set the distances expressions equal.
When you have solved for Caleb's time, please round the value to a whole number, then continue.








7:04
4:37
5:29


11: Thomas invested some of his $1,650 at 8% and the rest at 7% for one year. The annual simple interest from the 7% investment exceeds that from the other investment by $12. How much money was invested at 7%?
HInt: the interest from the 7% account is $12.00 more than the 8% account. Therefore, the interest from the 8% account plus $12.00 equals the interest from the 7% account.





$829.00
$960.00
$1,259.00


12: Cameron invested three times as much money at 7.95% as he invested at 6.5%. If his yearly simple interest is $282.26, how much money was invested at 6.5%?
Hint: Find an interest expression for each account. Then, those expressions added together equal the total interest.





$860.00
$900.00
$930.00


13: Jason wants to have simple interest income of $4,611 per year. If he found a bank that pays 8.7% simple interest per year, how much money will Jason need to deposit to meet his interest goal?
Hint: no table is necessary!

$12,300.00
$53,000.00
$24,060.00


14: Abigail has a credit card from Arctic Bank and another from Bagel Bank. She charged $130 more on the Arctic Bank card than on the Bagel Bank card. Arctic Bank charges 11% simple interest per year and Bagel Bank charges 18% per year. The yearly interest charge Abigail needs to pay is $226. How much money does Abigail owe Arctic Bank before interest charges in one year?
Hint: add the interest expressions to equal the total interest.





$860.00
$730.00
$560.00


15: Shelby had $6,200. She invested her savings in two mutual funds for one year. One fund is paying 5% simple interest and the other 8%. How much money did Shelby invest at 5% if the total annual interest is $421?
Hint: add the interest expressions to equal the total interest.





$1,000.20
$2,500.00
$1400.26

Answer 1

I will do two for you, then you can see how to do the rest. It really is a lot to ask someone to do fifteen problems for you, don't yuo agree?

1) Total speed of planes = 342 + 331 = 673 mph. (They are traveling in opposite directions, so you can add them together.)

The question becomes, how long will it take something to go 1616 miles at 673mph? Or 673(x) = 1616, or X = 1616/673
X = 2.4 hours

10) J = 35mph
C = J start time + 1.37 hours
C speed = 51
C has 1.37(35) miles to catch up, or 47.95 miles.

The question becomes, how long will it take C to go 47.95 miles traveling at 16mph? (You can't use the 51mph since J is moving as well, so C is only GAINING 16mph.)

47.95 / 16 = 3 hours (2.997) plus C's start time of 4:04 = 7:04.

Good luck!
(For interest problems, remember Interest = (Principal)(Rate)(Time), where rate is the % and time is the part of a YEAR.)

Answer 2

a fast way to answer these questions is to take the answers and figure it out backwards.

For #1 however, it is easy to see, you just keep adding the distance they travel each hour. (341+332) 673 miles per hourlook at what answer is closest to how many miles they have to get to.

For #2 multiply the 30 kph times the answers, 270miles, 225 miles and 180 miles. THen divide these by the answer plus the 3 hours: 12, 10.5 and 9 You get 22.5, 21.4 and 20. 20 is the speed at which the first person is travelling, and thus the answer is #3.

Get it?

Answer 3

you'll learn much better if you do that on your own....

i'm hoping teachers check Yahoo Answers these days...

Answer 4

If you dont get things you should really ask your teacher.