Question

От ленты отрезали 20%, а потом ещё 30% от оставшейся части. После этого осталось ещё 140 метров. Сколько метров ленты было изначально? Напишите решение и ответ.

Answer 1

Пусть вся лента будет х метров,тогда
х- 0,2х-0,3х=140
х-0,5х=140
0,5х=140
х=140:0,5
х=280 
Ответ 280 метров ленты было изначально

Answer 2

Problem Analysis

We are given that a piece of tape was initially cut by 20%, and then an additional 30% was cut from the remaining piece. After these two cuts, there is still 140 meters of tape left. We need to determine the length of the tape initially.

Solution

Let's assume the initial length of the tape is x meters.

The first cut reduces the length of the tape by 20%, leaving 80% of the original length. Therefore, the length after the first cut is 0.8x meters.

The second cut reduces the remaining length by 30%, leaving 70% of the length after the first cut. Therefore, the length after the second cut is 0.7 * 0.8x meters.

According to the problem, the length after the second cut is 140 meters. So we can set up the following equation:

0.7 * 0.8x = 140

Now we can solve this equation to find the value of x.

Calculation

Let's solve the equation:

0.7 * 0.8x = 140

Multiplying 0.7 and 0.8:

0.56x = 140

Dividing both sides by 0.56:

x = 140 / 0.56

Calculating the value:

x = 250

Answer

The initial length of the tape was 250 meters.

Explanation

The initial length of the tape was 250 meters. After the first cut of 20%, the length was reduced to 200 meters. Then, after the second cut of 30% from the remaining length, the final length was 140 meters.