The two dressmakers were brought the same number of meters of fabric. One uses 12m per day and the other 9m per day.

The two dressmakers were brought the same number of meters of fabric. One uses 12m per day and the other 9m per day. The second one ran out of fabric 5 days later. How much fabric did you bring for each?

Let x be the amount of the brought fabric; then the time during which the first dressmaker used it is x / 12, the time during which the second one is used up is x / 9
Let’s make the equation
X / 9-x / 12 = 5
We bring to a common denominator
4x-3x / 36 = 5
We give similar terms
X / 36 = 5
By the property of proportion, we obtain
X = 36 × 5
X = 180
Answer: 180