2 men produce boxes. A young man makes 7200 boxes in 200 minutes. An old man makes 300 in the same time.?

Question

2 men produce boxes. A young man makes 7200 boxes in 200 minutes. An old man makes 300 in the same time. Working together, how long to produce 7200 boxes?

Answer 1

Look at it in terms of boxes produced per minute.

The young man produces 7200 boxes in 200 minutes. Dividing you get 36 boxes a minute.

The old man produces 300 boxes in 200 minutes. Dividing you get 1.5 boxes a minute.

Working together they would produce the sum of these (37.5 boxes) a minute.

Now you can write an equation:
Let t be the time in minutes.

36t + 1.5t = 7200
37.5 t = 7200

t = 7200 boxes / 37.5 boxes/minute
t = 192 minutes

Answer 2

In 1 minute, the young man makes 7200/200=36 boxes. The old man makes 300/200 =1.5 boxes.
together, they make 37.5 boxes in 1 minute.
Together, to produce 37.5 boxes, 1 minute
1 box is 1/37.5 minute
7200 boxes in 7200(1/37.5) minutes=192 minutes.

Answer 3

300 +7200 boxes = 200 minutes
=> 7500 boxes= 200
=> 1 box = 200/7500
=> 7200 boxes = 200/7500 * 7200

QED

Answer 4

192 min.