"Math Riddles"

I Am a Three Digit Number

I am a three digit number.

My tens digit is five more than my ones digit.

My hundreds digit is eight less than my tens digit.

What number am I?

A:
Number 194.

A large truck is crossing a bridge

A large truck is crossing a bridge 1 mile long. The bridge can only hold 14000 lbs, which is the exact weight of the truck. The truck makes it half way across the bridge and stops. A bird lands on the truck. Does the bridge collapse? Give a reason.

A:
No it does not collapse. Because it has driven a half mile - you would subtract the gas used from the total weight of the truck.

Four members of a band …

Four members of a band are walking to a night concert. They decide to take a shortcut, but must cross a bridge. Luckily they have one flashlight.

Because of the varying size of their instruments, it takes each member a different amount of time to cross the bridge – it takes the first person one minute, the second person two minutes, the third person five minutes and the fourth person ten minutes.

They must cross the bridge in pairs, travelling at the slower speed so if the one minute person went with the ten minute person, it would take a total of ten minutes.

Since there is only one flashlight, one person must come back across the bridge, then another pair can cross.

They only have 17 minutes to cross the bridge and still get to the concert on time. What order should they cross to get everyone across and get to the concert?

A:
First, the one minute person and the two minute person must cross the bridge, for a total of two minutes. Then the one minute person should come back with flashlight - total of three minutes. The five minute person and the ten minute person cross together next, making the total thirteen minutes. Now the two minute person goes back and (total now fifteen minutes) and gets the one minute person and they cross together bringing the total to seventeen minutes.

Train Journey

Mr. Grumper grumbles about bad time-keeping trains like everybody else. On one particular morning he was justified, though.

The train left on time for the one hour journey and it arrived 5 minutes late. However, Mr. Grumper’s watch showed it to be 3 minutes early, so he adjusted his watch by putting it forward 3 minutes. His watch kept time during the day, and on the return journey in the evening the train started on time, according to his watch, and arrived on time, according to the station clock.

If the train traveled 25 percent faster on the return journey than it did on the morning journey, was the station clock fast or slow, and by how much?

A:
The station clock is 3 minutes fast. The morning journey took 65 minutes, and the evening journey therefore took 52 minutes, and the train arrived 57 minutes after it should have left, that is, 3 minutes early.

If you have three oranges

If there are three oranges and you take away two, how many will you have?

A:
Two. You took TWO

6 in roman

After teaching his class all about roman numerals (X = 10, IX=9 and so on) the teacher asked his class to draw a single continuous line and turn IX into 6. The only stipulation the teacher made was that the pen could not be lifted from the paper until the line was complete.

A:
Draw an S in front of the IX and it spells SIX. No one said the line had to be straight :)

Canaries and cages

I am the owner of a pet store. If I put in one canary per cage, I have one bird too many. If I put in two canaries per cage, I have one cage too many. How many cages and canaries do I have?

A:
I have 3 cages and 4 canaries

Age of father and son

The ages of a father and son add up to 66. The father’s age is the son’s age reversed.

How old could they be? (3 possible solutions).

A:
51 and 15. 42 and 24. 60 and 06.

The Missing Dollar

Three friends check into a motel for the night and the clerk tells them the bill is \$30, payable in advance. So, they each pay the clerk \$10 and go to their room. A few minutes later, the clerk realizes he has made an error and overcharged the trio by \$5.

He asks the bellhop to return \$5 to the 3 friends who had just checked in.

The bellhop sees this as an opportunity to make \$2 as he reasons that the three friends would have a tough time dividing \$5 evenly among them; so he decides to tell them that the clerk made a mistake of only \$3, giving a dollar back to each of the friends.He pockets the leftover \$2 and goes home for the day!

Now, each of the three friends gets a dollar back, thus they each paid \$9 for the room which is a total of \$27 for the night.

We know the bellhop pocketed \$2 and adding that to the \$27, you get \$29, not \$30 which was originally spent.

Where did the other dollar go????

A:
The facts in this riddle are clear: There is an initial \$30 charge. It should have been \$25, so \$5 must be returned and accounted for. \$3 is given to the 3 friends, \$2 is kept by the bellhop - there you have the \$5. The trick to this riddle is that the addition and subtraction are done at the wrong times to misdirect your thinking - and quite successfully for most. Each of the 3 friends did indeed pay \$9, not \$10, and as far as the friends are concerned, they paid \$27 for the night. But we know that the clerk will tell us that they were charged only \$25 and when you add the \$3 returned with the \$2 kept by the bellhop, you come up with \$30.
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