Arthur is organising his collection of DVDs. He has 112 altogether. The ratio of comedy films to
action to horror is 6 : 7 : 3
How many of each type of DVD does he have?
Comedy
Action
Horror

42 Comedy, 49 Action, 21 Horror

Step-by-step explanation:

6 comedy : 7 action : 3 horror = 16 parts or if you think of it as a fraction, 16 is the denominator and the numbers for each ratios are the numerators

112 (the total)/16 = 7 movies per part

6 parts of comedy = 6 x 7 = 42

7 parts action = 7 x 7 =49

3 parts horror = 3 x 7 = 21

Another way to think of it is:

(ex. comedy)

6/16=x/112

(CROSS MULTIPLY HERE)

16x=672

x=42

since your problem is x^4 = 81, what you have to undeo is the "to the fourth power" part.

the inverse (opposite operation) of "to the fourth power" is "to the fourth root".

  (x^4) ^ ¼   = 81 ^ ¼  

  81 = 3^4     so (3 ^ 4) ^ ¼   =   3 ^ 1   = 3

by hand: (3 ^ 4) ^ ¼   =   3 ^ (4 x ¼) = 3 ^ 1   = 3   (when you take a power to a power, multiply the exponents.)

or, do it by calculator. one way of finding the fourth root is to use ^ (1/4)

step-by-step explanation: