Solved the question 9, 10, 11, 12, 13, 14
Class 7th
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Solved the question 9, 10, 11, 12, 13, 14
Class 7th
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Questions
(i) The sum of three numbers is . If two of them are and , find the third number.
(ii) The sum of two consecutive integers is 39. Find the two integers.
(iii) One-third of a number when added to 1 gives 15. Find the number.
(iv) What is the number which gives -24 when (-46) is subtracted from it?
(v) What are prime numbers? Write all prime numbers between 60 and 80.
(vi) Evaluate the given equation 2.789×6.328 and round off to the hundredth place.
Answers
(i) Step 1: Add the two numbers given.
Find the LCM of the denominators i.e. 12 and 18.
LCM of 12 and 18 = 2×2×3×3 = 4×9 = 36
Make the denominators equal.
Add the numerators and let the denominator be the same.
Step 2: Subtract from .
Find the LCM of the denominators i.e. 63 and 36.
LCM of 63 and 36 = 3×3×4×7 = 9×28 = 252
Make the denominators equal.
Add the numerators and let the denominator be the same.
Simplify the fraction.
∴ The third number is .
(ii) Let one of the numbers be 'y'.
Our equation now would be ⇒
Step 1: Simplify the equation.
Step 2: Subtract 1 from both sides of the equation.
Step 3: Divide 2 from both sides of the equation.
∴ One of the numbers is ⇒ y = 19
∴ The other number is ⇒ y+1 = 19+1 = 20
(iii) We have to solve this equation for this question ⇒
Step 1: Subtract 1 from both sides of the equation.
Step 2: Multiply 3 from both sides of the equation.
∴ The number is 42.
(iv) To find the number we need to solve this equation ⇒
Step 1: Simplify both sides of the equation.
Step 2: Subtract 64 from both sides.
∴ The number is (-88).
(v) Numbers that are divisible to itself ae known as prime numbers. There are only 2 factors for a prime number. They are one and the number itself.
Prime numbers between 60 and 80 are ⇒ 61, 67, 71, 73, and 79.
(vi) 2.789×6.328 = 17.648792
When we round this number we get ⇒ 17.65
Answer:
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