# Water reservoir

One drain hole emptied the water from the tank for 20 hours, with the second drain for 30 hours. How long will the water drain from this tank if we open two drains simultaneously?

Result

t =  12 h

#### Solution:

t*(1/20 + 1/30)=1

5t = 60

t = 12

Calculated by our simple equation calculator.

Leave us a comment of example and its solution (i.e. if it is still somewhat unclear...):

Be the first to comment!

#### To solve this verbal math problem are needed these knowledge from mathematics:

Looking for help with calculating harmonic mean? Looking for a statistical calculator? Need help calculate sum, simplify or multiply fractions? Try our fraction calculator. Do you have a linear equation or system of equations and looking for its solution? Or do you have quadratic equation?

## Next similar examples:

1. Hectoliters of water
The pool has a total of 126 hectoliters of water. The first pump draws 2.1 liters of water per second. A second pump pumps 3.5 liters of water per second. How long will it take both pumps to drain four-fifths of the water at the same time?
2. Theorem prove
We want to prove the sentence: If the natural number n is divisible by six, then n is divisible by three. From what assumption we started?
3. The tank
The tank had 9 inflows to be filled in 21 days. After 9 days, 3 trips out. How many days did the remaining 6 tributaries fill the tank?
4. Three people
Three people start doing a work at a same time. The first worked only 2 hours. The second ended 3 hours before the end. On an individual basis, it would take the first time to do the work 10 hours, second 12 hours and 15 hours third. How many hours did it.
5. Novak
Novak needed to dig up three of the same pit in the garden. The first pit dug father alone for 15 hours. His second dig son helped him and it did that in six hours. The third pit dug son himself. How long it took him?
6. Turners
Two turners perform joint work in 3 hours. The first turner would perform the job himself in 7 hours. How long would the same job last for a second turner if he worked alone?
7. Simple equation 6
Solve equation with one variable: X/2+X/3+X/4=X+4
8. Painters 4
One painter will do the job for 12 days. After a 4 1/3 day he comes second to help him and complete work together for 8 days. How long would work the second painter himself?
9. Painters
The first team of painters would paint bridge in 15 days, the second in 10 days. After 3 days of working together second team goes out and continue only first team. How many days took second team to finish painting the bridge?
10. Three monks
Three medieval monks has task to copy 600 pages of the Bible. One rewrites in three days 1 page, second in 2 days 3 pages and a third in 4 days 2 sides. Calculate for how many days and what day the monks will have copied whole Bible when they begin Wednesd
11. Minute average
In a factory, four workers are assigned to complete an order received for dispatching 1400 boxes of a particular commodity. Worker A takes 4 mins per box, Worker B takes 6 minutes per box, C takes 10 mins per box, D takes 15 mins per box. Find the average.
12. Tonic
One package tonic consume Mom 12 weeks and daughter for 14 weeks. 4 weeks they use the same cream together and then only daughter. How many weeks endured tonic to daughter then?
13. Invitations
For every 5 minutes writes Dana 10 invitations, while Anna 14 invitations. How long will write together 120 invitations?
14. Bricklayers
When a bricklayer works himself to redeem the house in 8 days, the other bricklayer will be finished in 10 days. How long will it take to make 3 such houses together?
15. Six years
In six years Jan will be twice as old as he was six years ago. How old is he?
16. Our house
Our house would paint four painters in 14 days. How long could it paint five painters? How long will it take if two other painters will come to help after 5 days?
17. Six workers
Six workers planned to repair the roof in 5 days. After two days, two workers get sick. How long will the remaining workers complete the roof at the same rate of work?