Turn on thread page Beta
 You are Here: Home

# IQ question for you ppl watch

Announcements
1. There are 2 non-uniform wooden sticks, both of which can burn for a life-time of exactly 30min. How would you use the 2 sticks to time 45min exactly?

Condition: You are only allowed to use the 2 sticks and a source of fire
2. (Original post by equili3rium)
There are 2 non-uniform wooden sticks, both of which can burn for a life-time of exactly 30min. How would you use the 2 sticks to time 45min exactly?

Condition: You are only allowed to use the 2 sticks and a source of fire
i don't get it... burn one whole one then half of the other?
3. (Original post by equili3rium)
There are 2 non-uniform wooden sticks, both of which can burn for a life-time of exactly 30min. How would you use the 2 sticks to time 45min exactly?

Condition: You are only allowed to use the 2 sticks and a source of fire
ahh i would eat the wooden sticks
4. Wouldn't you just put the sticks like this:

_____
....._____

But right next to each other, so when one is half way through at 15mins it lights the other one which then has 30mins to burn?
5. put the sticks together, burn them, and blow them out after 45 mins
6. (Original post by elpaw)
put the sticks together, burn them, and blow them out after 45 mins
Lol.

I think the answer is, set one alight, when it is finished, light the other at both ends. This accounts for the possibility of the stick burning faster at one end than another.
7. (Original post by JamesF)
Lol.

I think the answer is, set one alight, when it is finished, light the other at both ends. This accounts for the possibility of the stick burning faster at one end than another.
ahhhhhh yes
8. good
9. (Original post by equili3rium)
good
good what?
10. Light the first one on both sides. This will make 15 mins. Then immediately light the other one on one side. 15 + 30 = 45. Tadaaa. You have to assume that both ends of the stick will burn equally though.

Sorry, someone's already answered it, but I wanted to anyways, tee hee.

The version of this that I was made to solve was:

You have two sticks that burn for 1 hr, how do you measure 45 mins?

Very similar to the other one. Anyone want to answer it?
11. (Original post by vavavoom)
Light the first one on both sides. This will make 15 mins. Then immediately light the other one on one side. 15 + 30 = 45. Tadaaa. You have to assume that both ends of the stick will burn equally though.

Sorry, someone's already answered it, but I wanted to anyways, tee hee.

The version of this that I was made to solve was:

You have two sticks that burn for 1 hr, how do you measure 45 mins?

Very similar to the other one. Anyone want to answer it?
do u light both ends of no. 1 and one end of no.2 when no. 1 has burnt out u light other end of no 2 and when no.2 is burnt out, 45 min has elapsed?
12. (Original post by lgs98jonee)
do u light both ends of no. 1 and one end of no.2 when no. 1 has burnt out u light other end of no 2 and when no.2 is burnt out, 45 min has elapsed?
Correct~!
13. (Original post by vavavoom)
Correct~!
yippeeee
14. Okay people this questions taken from the Mensa Home IQ Test:

A Certain tank holds 20 gallons of water. When a tap over it is turned on water flows from it into the tank at a rate of 4 gallons a minute. When a plug in the bottom of the tank is pulled out water drains away from the tank at the rate of 6 gallons a minute.

Question:
The tank is empty with the plug in. The tap is turned on for 4 minutes. The plug is then pulled out with the tap left on for another 6 minutes. How many gallons will be left in the tank at the end of this time?
15. (Original post by Fallen Angel)
Okay people this questions taken from the Mensa Home IQ Test:

A Certain tank holds 20 gallons of water. When a tap over it is turned on water flows from it into the tank at a rate of 4 gallons a minute. When a plug in the bottom of the tank is pulled out water drains away from the tank at the rate of 6 gallons a minute.

Question:
The tank is empty with the plug in. The tap is turned on for 4 minutes. The plug is then pulled out with the tap left on for another 6 minutes. How many gallons will be left in the tank at the end of this time?
after 4 mins, 16 gallons are in. after plug pulled out, water flows out at 2 gall/min, for 6 mins = 12 gallons, therefore 4 gallons left over
16. A Certain tank holds 20 gallons of water. When a tap over it is turned on water flows from it into the tank at a rate of 4 gallons a minute. When a plug in the bottom of the tank is pulled out water drains away from the tank at the rate of 6 gallons a minute.

Question:
The tank is empty with the plug in. The tap is turned on for 4 minutes. The plug is then pulled out with the tap left on for another 6 minutes. How many gallons will be left in the tank at the end of this time

4*4 = 16 gallons to begin with
-6*6 = -36 gallons drained out
4*6 = 24 gallons coming in

begin with 16, so if the ratio of water going out to water coming in is 3:2, the tank will lose 12 gallons, leaving 4. because the plug drains faster than the tap, the maximum amount of water is 16.

Turn on thread page Beta
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: March 7, 2004
Today on TSR

### Edexcel GCSE Maths Unofficial Markscheme

Find out how you've done here

### AQA Maths Paper 1 exam discussion

Poll

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE