8TH GRADE MATH WORKSHEET 3 ANSWER

About "8th grade math worksheet 3 answer"  

8th grade math worksheet 3 answer :

Here we are going to see 10 practice questions of mixed topics. We have been preparing this set of questions in order to test how you understood the topics.

Practice questions of mixed topics in 8th grade math

Question 1 :

What fraction should be added with -4/9 to get 6/17 ?

(A)   104/163      (B)   136/151       (C)   122/153

Solution :

Let "x" be the required fraction

(-4/9) + x  =  6/17

Add both sides by 4/9

x  =  (6/17) + (4/9)  

  =  (54 + 68)/153

  =  122/153

Let us look into solution of next problem on "8th grade math worksheet 3 answer".

Question 2 :

Find for which value of x is the following equation true? 4^4x-7 = 4^{x - 1} .

(A) 2            (B) 3             (C) 4

Solution :

Since the base are same, we may equate the powers.

4x - 7  =  x - 1

Subtract both sides by x

4x - x - 7  =  -1

3x - 7  =  -1

Add both sides by 7

3x  =  -1 + 7

3x  =  6

Divide both sides by 3

x  =  6/3  =  2

Question 3 :

Express 412 x 10^-9 in standard form. 

(A) 41.2 x 10⁷       (B) 4.12 x 10^-7     (C) 4.12 x 10⁹

Solution :

412 x 10^-9  =  4.12 x 10² x 10^-9

  =  4.12 x 10^{(2 - 9)}

  =  4.12 x 10 ^-7

Question 4 :

Find the value of 5x - 6y - 8z if x = 2, y = 3 and z = -2.

(A) 5           (B) 8         (C) -18

Solution :

=  5x - 6y - 8z

=  5(2) - 6(3) - 8(-2)

=  10 - 18 + 16

=  26 - 18

=  8

Question 5 :

A number is 7 times greater than another number. If their sum is 96, find the numbers.

(A) 49, 51          (B) 84, 12         (C) 21, 75

Solution :

Let "x" and "7x" be two numbers 

x + 7x  =  96

8x  =  96

x  =  12

7x  = 7(12)  =  84

Hence the required numbers are 12 and 84.

Question 6 :

Which of the following are Pythagorean triplet?

(A) 12, 16, 20    (B) 9, 12, 15     (C) 10, 12, 34

Solution :

To prove the given numbers are in pythagorean triplet, we have to prove that the square of one term is equal to the sum of squares of the other numbers.

First let us take the numbers 12, 16, 20

20²  =  16² + 12²

400  =  256 + 144

400  =  400

Hence 12, 16, 20 are in pythagorean triplet.

Question 7 :

Which of the following is the cube of the even number?

(A) 343     (B) 729      (C) 1728

Solution :

Cube of a even number is also is even.

Hence 1728 is the cube of even number.

Question 8 :

Find the square root of 98464

(A) 272      (B) 242       (C) 212

Solution :

More examples please visit "Square root by long division method"

Hence the answer is 272.

Question 9 :

The sum of two numbers is 80 and their ratio is 3:5.Find the numbers.

(A) 30 and 50     (B) 18 and 30     (C) 21 and 35

Solution :

Let 3x and 5x be two numbers

3x + 5x  =  80

8x  =  80

x  =  80/8  =  10

3x  =  3(10)  =  30

5x  =  5(10)  =  50

Hence the required numbers are 30 and 50.

Question 10 :

Find the value of x ° if the lines AB and CD are parallel to each other

(A)   90°               (B)   123°            (C)   57°

Solution :

<AOB  =  360 - 246  =  114

<ACB  =  <AOB/2

  =  114/2

  =  57°

Hence the required angle is 57°.

Answers:

(1)  122/153

(2)  2

(3)   4.12 x 10^-7

(4)  8

(5)  12 and 84

(6)  12, 16, 20

(7)  1728

(8)  272

(9)  30 and 50

(10)  57

After having gone through the stuff given above, we hope that the students would have understood "8th grade math worksheet 3 answer"

Apart from the stuff given above, if you want to know more about "8th grade math worksheet 3 answer", please click here.

Apart from the stuff given on, if you need any other stuff in math, please use our google custom search here. 

You can also visit our following web pages on different stuff in math. 

WORD PROBLEMS

HCF and LCM  word problems

Word problems on simple equations 

Word problems on linear equations 

Word problems on quadratic equations

Algebra word problems

Word problems on trains

Area and perimeter word problems

Word problems on direct variation and inverse variation 

Word problems on unit price

Word problems on unit rate 

Word problems on comparing rates

Converting customary units word problems 

Converting metric units word problems

Word problems on simple interest

Word problems on compound interest

Word problems on types of angles 

Complementary and supplementary angles word problems

Double facts word problems

Trigonometry word problems

Percentage word problems 

Profit and loss word problems 

Markup and markdown word problems 

Decimal word problems

Word problems on fractions

Word problems on mixed fractrions

One step equation word problems

Linear inequalities word problems

Ratio and proportion word problems

Time and work word problems

Word problems on sets and venn diagrams

Word problems on ages

Pythagorean theorem word problems

Percent of a number word problems

Word problems on constant speed

Word problems on average speed 

Word problems on sum of the angles of a triangle is 180 degree

OTHER TOPICS 

Profit and loss shortcuts

Percentage shortcuts

Times table shortcuts

Time, speed and distance shortcuts

Ratio and proportion shortcuts

Domain and range of rational functions

Domain and range of rational functions with holes

Graphing rational functions

Graphing rational functions with holes

Converting repeating decimals in to fractions

Decimal representation of rational numbers

Finding square root using long division

L.C.M method to solve time and work problems

Translating the word problems in to algebraic expressions

Remainder when 2 power 256 is divided by 17

Remainder when 17 power 23 is divided by 16

Sum of all three digit numbers divisible by 6

Sum of all three digit numbers divisible by 7

Sum of all three digit numbers divisible by 8

Sum of all three digit numbers formed using 1, 3, 4

Sum of all three four digit numbers formed with non zero digits

Sum of all three four digit numbers formed using 0, 1, 2, 3

Sum of all three four digit numbers formed using 1, 2, 5, 6