Question

Three-sevenths of a number is 21. Find the number.

Answer 1

Answer:

Step-by-step explanation:

The number is 49, First do 21 / 3 to find what 1/7 of the number is. We get 7, so we know 1/7 is 7 so if we do 7 x 7 we will have 7/7 or one whole and 7x7 is 49. Hope this helps

Answer 2

Answer:

The number is 49

Step-by-step explanation:

Let the number be x

From the question, $\frac{3}{7}$  of   x   =   21

                                 $\frac{3}{7}$ × x  = 21

                                  $\frac{3x}{7}$ = 21

Multiply both-side of the equation by 7

                                    $\frac{3x}{7}$ × 7 = 21 × 7

(On the left-hand side of the equation, 7 at the numerator will cancel-out 7 at the denominator leaving us with just 3x)

                                      3x  = 147

Divide both-side of the equation by 3

                                       $\frac{3x}{3}$ =  $\frac{147}{3}$

(On the left-hand side of the equation 3 at the numerator will cancel-out 3 at the denominator, while on the right-hand side of the equation 147 will be divided by 3)

                                                   

                            x  = $\frac{147}{3}$

                              x=49

Therefore the number is 49