Two brothers decide that a 21-hour task is to be divided so thst the older brother works twice as long as the younger brother. How long must the older brother work?

14 hours

Step-by-step explanation:

Let's call the task 3x

The older bro does twice as younger so it would be 2x long and younger brother work x long

Since the totsl of work is 3x = 21 x woul be 21:3 = 7

the older brother must work 2 * 7 = 14 hours long

Answer: the older brother must work for 14 hours.

Step-by-step explanation:

Let x represent the number of hours that the younger brother must work.

Two brothers decide that a 21-hour task is to be divided so that the older brother works twice as long as the younger brother. This means that the number of hours that the older brother must work is expressed as 2x.

Since the total number of hours is 21, then

x + 2x = 21

3x = 21

x = 21/3

x = 7

The number of hours that the older brother must work is

2x = 2 * 7 = 14 hours