Post a New Question

arithmetics

posted by .

hello can someone help me understand these questions? It's for a test that has arithmetic questions on it and Im trying to study them but I cant do that unless I actually know how to do them.

#5 A carpenter needs 4 boards, each 2 feet 9 inches long. If wood is sold only by the foot, how many feet must he buy? the answer is 11 but how do you get 11?

#7On a blueprint in which 2 inches represent 5 feet, the length of a room mesure 7 1/2 inches. The actual length of the room is? 18 3/4

#8Durning a 25% sale, an article sells for $375, what was the original price of this article?

#10A piece of wood 35 feet 6 inches long was used to make 4 shelves of equal lenth. The lenth of each shelf was? 8 feet 10 1/2 inches

#21 A crate containing a tool that weighs 12 pounds. If the tool weighs 9 pounds, 9 ounces, how much does the crate weigh? 2 pounds,7 ounces

#22The area of a room mesuring 12 feet by 15 feet is? 20 square yards.

#28If 1/2 cup of spinach contains 80 calories and the same amount of peas contains 300 calories, how many cups of spinach have the same caloric content as a 2/3 cup of peas?
2 1/



#5 A carpenter needs 4 boards, each 2 feet 9 inches long. If wood is sold only by the foot, how many feet must he buy? the answer is 11 but how do you get 11?

You need to multiply 4 times 2 3/4 to find the total amount of board feet the carpenter needs. (9 inches is 9/12 or 3/4 of a foot.) Do you get 11 by doing this?

#7On a blueprint in which 2 inches represent 5 feet, the length of a room mesure 7 1/2 inches. The actual length of the room is? 18 3/4

The easiest way to do this problem is to set up a ratio. Let x equal the blueprint measure of the room.

Five feet is to two inches as 18 3/4 feet is to x inches
2 / 5 x 7 1/2 / x

Cross multiply -- 2x = 5(7 1/2)


#8Durning a 25% sale, an article sells for $375, what was the original price of this article?

You can set up a simple equation, with x = the original price.

.75 x = 375


_________________________

This should get you started. Please try to work out the other problems and post your answers here. We'll be glad to check your work.




#5. to get the 11 they just multiplied 4 by 2.75.

(2 feet 0 inches = 2 feet + 9/12 feet
9/12=.75
so 2 feet 9 inches = 2/75 feet)

This is an unrealistic answer since it ignores the loss you will have when you cut the 11 feet into the 4 pieces.

#7 set up a ratio

2 in = 5 feet
7.5 in = x feet
2/7.5 = 5/x
2x = 7.5 x 5
2x=37.5
x=18.75
so the room is 18 3/4 feet

#8 the $375 represents 75% of the original price.
so or. price = 375/.75
= 500 (test it by taking 1/4 away from 500)

#10 35feet 6 inches = 35.5 feet
so divide 35.5 by 4 to get their 8.875 feet

(.875 = 7/8, so 3/8 of a foot
= 7/8 x 12
= 10.5 inches, so 10 1/2 inches)

((Man, this working in non-metric is for the birds!!!!, not used to it anymore))

#21
take 12 lbs - 9 lbs, 9 oz
= 12 - 9 9/16
= 192/16 - 153/16
= 39/16
= 2 7/16 lbs
= 2 lbs and 7 ounces

gee, this would be so easy in Kg and grams.

#22 12 feet by 15 feet gives you 180 square feet.
there are 9 square feet in a square yard ,so 180/9 = 20 square yards

#28

set up 2 ratio problems

first the peas:
1/2 cup of peas = 300 cal
2/3 cup of peas = x cal
(1/2)/(2/3) = 300/x

.
.
x = 400

so you want 400 cal to come from the spinach

(1/2)/x = 80/400

solve to get x = 5/2

so 2 1/2 cups of spinach are needed


this is difficult for me...
#5 A carpenter needs 4 boards, each 2 feet 9 inches long. If wood is sold only by the foot, how many feet must he buy? the answer is 11 but how do you get 11?

You need to multiply 4 times 2 3/4 to find the total amount of board feet the carpenter needs. (9 inches is 9/12 or 3/4 of a foot.) Do you get 11 by doing this?

yes I do but how do you get 2 3/4??

I don't get this setting up a ratio buisness???


yes I do but how do you get 2 3/4??

Each board is 2 feet, 9 inches long. A foot has 12 inches, so 9 inches is 9/12 of a foot. This fraction reduces to 3/4. So each board is 2 3/4 feet long.

I don't get this setting up a ratio buisness???

This site explains how to set up a ration and find an unknown.

http://www.purplemath.com/modules/ratio.htm

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Need Preperation Help

    I have a test on Hamlet soon and I'm just wondering if anyone know sites that have test-like questions?
  2. math

    algebra in 8th your teacher is giving you a test worth 100 points containing 40 questions. There are two-point and four-point questions on the test. how many of each type of questions are on the test?
  3. MATH

    Wendy answered 85% of the questions on her history test correctly. There were 40 questions on the test and all the questions had equal value. How many questions did Wendy NOT answer correctly on her test?
  4. Stats

    An instructor gives a test with 20 multiple choice questions. There are 4 responses per questions and only one choice correct. The test also has 30 True/False questions. Determine the probability a student randomly guessing on all …
  5. Math ( Percents as Ratios)

    Sue receives a test score of 75% on a test with 20 questions. How many did she get correct?
  6. mathematics

    Jake correctly answered 15 out of 25 questions in Test 1 and 18 out of 25 questions on test 2. On Test 3 he missed 5 out of 27 questions. Which test had the best score?
  7. Science study skills

    What is the importance of questioning in the SQ3R system?
  8. science

    What is the importance of questioning in the SQ3R system?
  9. Math

    I do not understand this problem, and I must write an inequality for it too: Nilsa is working on a 60 minute math test. There are 20 questions on the test. If it takes her 20 minutes to complete 12 of the questions, what is the greatest …
  10. math

    On a 28-question test, there are 2-point questions, 4-point questions, and 5-point questions. The test is worth a total of 100 points. There are twice as many 2-point questions as 5-point questions on the test. How many 2-point questions …

More Similar Questions

Post a New Question