Answer:
36 comedy dvd's, 63 action dvd's and 45 horror dvd's
Explanation:
To know the amount of each type of DVD Arthur has, we need to sum the values of the ratios, and then multiply the total value of dvd's by the fraction that represents each amount of DVD:
4 + 7 + 5 = 16
Fraction of comedy DVD's: 4/16
Fraction of action DVD's: 7/16
Fraction of horror DVD's: 5/16
Then, we multiply these fractions by the total number of DVD's:
Number of comedy DVD's: 144 * 4/16 = 36
Number of action DVD's: 144 * 7/16 = 63
Number of horror DVD's: 144 * 5/16 = 45