Câu hỏi 1:
The average of three numbers is 1988. The first number is 1984. The third number is 2 units more than the second number. Find the third number.

Câu hỏi 2:
The average of 5 consecutive odd numbers is 123. Find the greatest number.
Câu hỏi 3:
Which of the following fractions is equal to 2/3?

Câu hỏi 4:
The average of two numbers is 95. The first number is 2/3 of the second number. Find the first number
Câu hỏi 5:
Fill in the blank with the correct number: 6/100 kg = .... kg

Câu hỏi 6:
The sum of two fractions is 45/23 and the first fraction is one quarter of the second fraction. Find the first fraction.

Câu hỏi 7:
The sum of twonumbers is 463 and three are eighteen even numbers between these numbers. Find the greater number.

Câu hỏi 8:
Which of the following fractions is the greatest number?

Câu hỏi 9:
The average of two numbers is 95. The first number is 2/3 of the second number. Find these two numbers.

Câu hỏi 10:
The sum of the number of lions and monkeys in a zoo is 40 and lions are 1/3 the number of monkeys. How many monkeys are there in the zoo?
 

Câu 1 :Each of cars can take 8 people. How many cars needed to take 124 people?

Câu 2 : How many integer numbers between 200 and 300 are there for which the hundreds digit equals the sum of the other two digits?

Câu 3 : The average of five numbers is 20. The average of the five number is 18 when one of the numbers is chaned to 4. What is the orginal value of the changed number?

Câu 4 :A book has 250 pages starting at number 1. How many digits are there in the page numbers of the book?

Câu 5 : Find A, if A is 3 less than the average of 48; 55; 29 and A. The value of A is…

Câu 6 : The sum of denominator and numerator of a fraction is 121 and the fraction is equal to 4/7. Find the denominator of the fraction?

Câu 7 : The sum of two numbers is equal to 77. If the first number is multiplied by 8 and the second by 6, the two product are equal. The larger of these numbers is…

Câu 8 : Which is the greatest 2 - digit number divisible by 2, 3 and 4?

Câu 9 : Calculate: (1 + 2/5) x 6/7.

Câu 10 : Give the number sequence: 1, 4, 7, 10, 13, … Find the 15th term of the number sequence.

1: the perimeter of a circle is 15,7 dm. Its's area is...cm2

2: the ratio of the number of girls to the number of boys in a classroom is 5:4. When 10 girls left the classroom, the ratio of the number of boys to the number of girls became 4:3. How many students were in the classroom at first?

3: 47/250 dm3=...cm3

4: At the party 60% of the boys are dancing with 80% of the girls. How many people are dancing if there are 35 people ( A pair cludes only one boy and one girl)

5: An aquarium is 8dm deep, 12 dm long and 0,3 m wide. What is the volume of the aquarium in cubic centimeter?. Answer: the volume of the aquarium is...cm3

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 13 to 50.

          Carbon dating can be used to estimate the age of any organic natural material; it has been used successfully in archeology to determine the age of ancient artifacts or fossils as well as in a variety of other fields. The principle underlying the use of carbon dating is that carbon is a part of all living things on Earth. Since a radioactive substance such as carbon-14 has a known half-life, the amount of carbon-14 remaining in an object can be used to date that object.
          Carbon-14 has a half-life of 5,570 years, which means that after that number of years, half of the carbon- 14 atoms have decayed into nitrogen-14. It is the ratio of carbon-14 in that substance that indicates the age of the substance. If, for example, in a particular sample the amount of carbon-14 is roughly equivalent to the amount of nitrogen-14, this indicates that around half of the carbon-14 has decayed into nitrogen-14, and the sample is approximately 5,570 years old.
          Carbon dating cannot be used effectively in dating objects that are older than 80,000 years. When objects are that old, much of the carbon-14 has already decayed into nitrogen-14, and the molecule amount that is left doesn’t provide a reliable measurement of age. In the case of older objects, other age-dating methods are available, methods which use radioactive atoms with longer half-lives than carbon has

It can be inferred from the passage that if an item contains more carbon-14 than nitrogen-14, then the item is______.

A. not as much as 5,570 years old

B. too old to be age-dated with carbon-14

C. too radioactive to be used by archeologists 

D. more than 5.570 years old