Puzzle 621
During a recent BrainBashers race meeting, the fastest driver managed to complete a lap with an average speed of 150 mph.
They managed to complete the first two fifths of the lap at a speed of 123 mph and the second two fifths of the lap at a speed of 164 mph.
At what speed was the final one fifth of the lap length covered?
The answer is not 176 mph.
Puzzle Copyright © Kevin Stone
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Hint
Adding the speeds won't work.
Answer
205 mph.
Reasoning
If we take the number of miles in a lap to be L miles and use Time = Distance ÷ Speed.
The first 2/5 are covered at 123 mph. Therefore, the time taken was [(2/5) x L] ÷ 123 hours.
The next 2/5 are covered at 164 mph. Therefore, the time taken was [(2/5) x L] ÷ 164 hours.
The last 1/5 is covered at y mph. Therefore, the time taken was [(1/5) x L] ÷ y hours.
The entire trip is covered at an average of 150 mph, and we can conclude that:
2L 2L L L
————— + ————— + ——— = ———
5x123 5x164 5y 150
Rearranging and simplifying gives:
1 1 2 2
——— = —— - ——— - ———
y 30 123 164
That means that y = 1 ÷ (1/30 - 2/123 - 2/164)
Using a calculator gives y = 205.
Puzzle 622
If I was in Florida and dropped a heavy ball into a bucket of water which was at a temperature of 45 °F and dropped another identical ball into an identical bucket of water at a temperature of 25 °F...
...which ball would hit the bottom of the bucket first?
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Hint
Remember that the question uses Fahrenheit °F.
Answer
The ball would reach the bottom of the 45 °F bucket first because the water is frozen in the 25 °F bucket!
Puzzle 623
Here are some less well known proverbs. What is the missing word in each?
Loyalty is worth more than {?}.
He that cannot pay in {?} must pay in person.
Shameful {?} is worse than shameful eating.
Don't say {?} until you are asked.
Payment in advance is {?} payment.
Puzzle Copyright © Kevin Stone
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Share link: https://www.brainbashers.com/puzzle/ztjy
Answer
Loyalty is worth more than money.
He that cannot pay in purse must pay in person.
Shameful leaving is worse than shameful eating.
Don't say no until you are asked.
Payment in advance is evil payment.
Puzzle 624
My first is in mammoth, but not in elephant.
My second is in racoon, but not in beaver.
My third is in dobbin, but not in horse.
My fourth is in koala, and in kangaroo.
My fifth is in tiger, but not in lion.
My last is in pony, but not in horse.
What am I?
Puzzle Copyright © Kevin Stone
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Share link: https://www.brainbashers.com/puzzle/zxzd
Hint
My first letter is M, and watch out for the 4th letter.
Answer
A monkey.
Reasoning
The 1st letter can be: M O
The 2nd letter can be: C O N
The 3rd letter can be: D B I N
The 4th letter can be: K O A
The 5th letter can be: T G E R
The 6th letter can be: P N Y
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