A rope, the first cut 38, the second cut 14, there are 24m left, how long is this rope?

A rope, the first cut 38, the second cut 14, there are 24m left, how long is this rope?

A: This rope was 64 meters long

A rope, the first cut 38, the second cut 14, there are 24m left, how long is this rope?

A: This rope was 64 meters long

1. A rope is 20 meters long. Cut off 1 / 5 of the total length for the first time. Cut off the remaining 5 / 8 for the second time. How many meters for the second time?
2. A rope is 20 meters long. How many meters will it be cut off in the second time?
3. A rope is 20 meters long. How many meters more than the first one in the second time?
4. A rope is 20 meters long. Cut off 1 / 5 of the total length in the first time and the remaining 5 / 8 in the second time. How many meters are left in this rope?
Don't use the equation, use the formula to answer well, and then offer a reward

1. 20 * (1-1 / 5) * 5 / 8 = 10m
2. 20 * (1-1 / 5) * 5 / 8 + 20 * 1 / 5 = 14m
3. 20 * (1-1 / 5) * 5 / 8-20 * 1 / 5 = 6M
4. 20 - (20 * (1-1 / 5) * 5 / 8 + 20 * 1 / 5) = 6M

After the first use of a rope, there are still 8 / 15 of the total length left. After the second use of 7.5 meters, there are still 8.5 meters left. How long is the original rope?

（8.5+7.5）÷8/15
=16÷8/15
=30 meters
The rope was 30 meters long

A rope, the first cut off 14 meters, the second cut off 8 meters, there are 13 left, this rope how long?

(14 + 8) / (1-13) = 22 / 23 = 33 (m) a: This rope used to be 33 meters long

The sum of a and B is 75, 1 / 5 of B is 3 less than 1 / 4 of a, B is ()
Please don't use the equation of degree 1 with 2 variables

(75+3*5)/9*5-3*5=35
Have you studied this pure arithmetic method
If you don't understand, I'll explain to you:
Since 1 / 5 of B is 3 less than 1 / 4 of a, I add 5 3, then 1 / 5 of B will be equal to 1 / 4 of A
Then divide the 90 in proportion, B = 5 / 9, a = 4 / 9
I want to find the number B, that is, 90 * 5 / 9 = 50
The final minus plus 15

For a project, team a and team B work together and complete it in 36 days; Team B and team C work together and complete it in 45 days; team a and team C work together and complete it in 60 days______ It will be finished in three days

1 △ [(136 + 160-145) △ 2], = 1 △ [145 × 12], = 1 △ 190, = 90 (days); answer: team a does it alone, it takes 90 days to complete. So the answer is: 90

There are two inlet pipes (A and C) and two drainage pipes (B and D) in the natatorium. It takes three hours for a to fill the empty pool with water by opening the inlet pipe, and five hours for C. It takes four hours for B and six hours for D to complete the full pool with water by opening the drainage pipe. Now there is one fifth of the pool water How many hours after the water tank starts to overflow?
The answer at the back of the book is 20 and 13 / 20.
My calculation is 24 and 3 / 10.

A, B, C and d turn for one hour each,
The workload of a round is 1 / 3-1 / 4 + 1 / 5-1 / 6 = 7 / 60
It is necessary to consider whether the water injection of pipe a overflows after each round
The sum of water injection is 1 / 3-1 / 4 + 1 / 5 = 17 / 60 < 1 / 3
(1－1/5)－7/60=41/60＞1/3
41/60－7/60=34/60＞1/3
34/60－7/60=27/60＞1/3
27 / 60-7 / 60 = 20 / 60 is exactly 1 / 3
After 4 rounds, it was just enough to inject water into tube a for 1 hour, but there was no overflow, and it entered the fifth round
20/60-7/60=13/60＜1/3
After 5 rounds, the first tube was injected with 13 / 60 △ 1 / 3 = 13 / 20
Total 5 × 4 + 13 / 20 = 20 and 13 / 20 hours
The answer is correct

A pool is equipped with a water inlet pipe and a drainage pipe. The pool can be filled in 4 minutes by opening the water inlet pipe, and the full pool can be drained out in 6 minutes by opening the drainage pipe. Now there are 13 dirty water in the pool. Master Li has to drain all the dirty water first, but he forgot to close the drainage pipe when filling with clean water. How long does it take to fill the pool with clean water?

(13 / 16) + 1 / 14-16 = 2 + 1 / 112 = 2 + 12 = 14 (minutes) a: it takes 14 minutes to fill with water

To complete a project, Party A will do it alone in 8 days, and Party B will do it alone in 10 days. With the cooperation of Party A and Party B, four fifths of the project can be completed in a few days

4/5÷（1/8+1/10）
＝4/5÷9/40
= 32 / 9 (days)