Answer:
119
Explanation:
The total number of people who had taken the survey is 420 wich is equivalent to 100%.
The percentage of people who drink coffee is 85%.
●●●●●●●●●●●●●●●●●●●●●●●●
Let x be the number of people drinking coffee
● 420 => 100%
● x => 85%
These values are proportional so we can cross-multiply them
● x*100 = 420*85
● x = (420*85)÷100
● x = 357
The number of people who drink coffee is 357.
■■■■■■■■■■■■■■■■■■■■■■■■■
Let y be the number of people who drink black coffee.
y is 1/3 of 357 since people who drink black coffee represent the third of the total number of people drinking coffee in general.
● To get y multiply 1/3 by the total number of people drinking coffee (357)
●y = (1/3)*357
● y = 119
119 is the number of people who drink black coffee