How to measure exactly 4 gallon of water from 3 gallon and 5 gallon jars, given, you have unlimited water supply from a running tap.
Step 1. Fill 3 gallon jar with water. ( 5p – 0, 3p – 3)
Step 2. Pour all its water into 5 gallon jar. (5p – 3, 3p – 0)
Step 3. Fill 3 gallon jar again. ( 5p – 3, 3p – 3)
Step 4. Pour its water into 5 gallon jar untill it is full. Now you will have exactly 1 gallon water remaining in 3 gallon jar. (5p – 5, 3p – 1)
Step 5. Empty 5 gallon jar, pour 1 gallon water from 3 gallon jar into it. Now 5 gallon jar has exactly 1 gallon of water. (5p – 1, 3p – 0)
Step 6. Fill 3 gallon jar again and pour all its water into 5 gallon jar, thus 5 gallon jar will have exactly 4 gallon of water. (5p – 4, 3p – 0)
We are done !
See also best riddles or new riddles.logicmathshort
Dean Sam and Castiel are three brothers.
Interestingly their current age is prime.
What's more interesting that difference between their ages is also prime.
How old are they?
Sam : 2
Dean : 5
Castiel : 7
7 - 2 = '5' is prime
7 - 5 = '2' is prime
5 - 2 = '3' is primelogicmathshort
Hockey Stick and ball cost $50. If the Stick cost $49 more than the ball. What is the cost of each ?
Hockey Stick $49.50 & ball $0.50.logicmathshort
The digits 0-9(0,1,2,3,4,5,6,7,8,9) can be rearranged into 3628800 distinct 10 digits numbers.
How many of these numbers are prime?
None. The sum of numbers from 0-9(0,1,2,3,4,5,6,7,8,9) is 45 and therefore can be divisible by 3 and 9.logicmathshort
Using eight eights and addition only, can you make 1000?
888 + 88 + 8 + 8 + 8 = 1000logicmath
How can you divide a pizza into 8 equal slices using only 3 straight cuts?
Cut 1: Cut the pizza straight down the middle into two halves.
Cut 2: Keeping the two halves in the place, cut the pizza straight down the middle at right angles to the first cut (you will be left with 4 equal quarters)
Cut 3: Pile the 4 quarters on top of each other and cut through the middle of the pile. You will be left with 8 equal slices.logicmath
A train leaves from Halifax, Nova Scotia heading towards Vancouver, British Columbia at 120 km/h. Three hours later, a train leaves Vancouver heading towards Halifax at 180 km/h. Assume there's exactly 6000 kilometers between Vancouver and Halifax. When they meet, which train is closer to Halifax?
Both trains would be at the same spot when they meet therefore they are both equally close to Halifax.logicmathshort
Find three positive whole numbers that have the same answer added together or when multiplied together.
1,2, & 3.
1 x 2 x 3 = 6 and 1 + 2 + 3 = 6logicmathshort
A clock chimes 5 times in 4 seconds. How many times will it chime in 10 seconds?
11 times. It chimes at zero and then once every second for 10 seconds.logicmathshort
If an electric train is going east at 60 miles an hour and there is a strong westerly wind, which way does the smoke from the train drift?
here is no smoke coming from electric trains.logicmath
You are standing in a pitch-dark room. A friend walks up and hands you a normal deck of 52 cards. He tells you that 13 of the 52 cards are face-up, the rest are face-down. These face-up cards are distributed randomly throughout the deck.
Your task is to split up the deck into two piles, using all the cards, such that each pile has the same number of face-up cards. The room is pitch-dark, so you can't see the deck as you do this.
How can you accomplish this seemingly impossible task?
Take the first 13 cards off the top of the deck and flip them over. This is the first pile. The second pile is just the remaining 39 cards as they started.
This works because if there are N face-up cards in within the first 13 cards, then there will be (13 - N) face up cards in the remaining 39 cards. When you flip those first 13 cards, N of which are face-up, there will now be N cards face-down, and therefore (13 - N) cards face-up, which, as stated, is the same number of face-up cards in the second pile.