Number Puzzles - Page 15 of 25

Cube with painted surface puzzle

May 10, 2014 by puzzler 2 Comments

Number Puzzle #92

red color cube puzzle

A 3x3x3 inches cube is painted with red color on all the outer surfaces. If the cube is cut into smaller cubes of 1*1*1 inches.

How many 1 inch cubes will have at least one surface painted ?

Check your answer:-

Click here to See Solution

Lets count:
All the corners will have 3 faces painted, there are total of 8 corners.
Cubes at the edge(except corners) will have 2 faces painted, there will a one such cube per edge, there are a total of 12 edges, thus 12 cubes will have 2 faces painted.
You can imagine one cube formed by exact center of a face will have only one face painted, there are a total of 6 faces in a cube, thus 6 such cubes will exists.

So total number of cubes with at least one face painted = 8 + 12 + 6 = 26

We can even confirm our calculation by counting the number of painted faces
Number of painted faces = 8*3 + 12*2 + 6 = 24 + 24 + 6 = 54 = 9*6(Each face of the original 3x3x3 cube is cut into 9 pieces.

How many days required?

May 7, 2014 by Puneet Leave a Comment

Number Puzzle #91

16 men can finish a job in 16 days, If after 4 days manpower is increased by 14, then How many days will be needed to finish the job?

–In Hindi–

16 aadmi 1 kaam ko 16 dino me pura karte hai agar 4 din baad 14 aadmi bada dete hain to kitne dino me kaam pura hoga?

Click here to See Answer

16 men can do a job in 16 days, after 4 days remaining work can be finished in 12 days by 16 men. But now as we have 14 more persons to do the job, so it can be finished in 12*16/30 = 6.4 days.

More explanation:-

16 men can finish a job in 12 days.

1 man can do the same job alone in 12*16 days.

30 men can do the same job in 12*16/30 days.

How many toys?

May 1, 2014 by Rajat 3 Comments

Number Puzzle #90

A man had Rs.900 and brought some toys with all the money. Out of which 5 toys were defected. He sold all the remaining toys by increasing the price by Rs.2 and made a profit of Rs.80.
What is the no.of initial toys and the initial cost of toys?

Check your answer, Number of Toys:-

Check your answer, Initial Cost:-

Click here to See Solution

Let assume he had x toys and bought it for Rs.y per piece.
Now, we can form these two equations from these
x*y = 900;//Total cost
(y+2)(x-5) = 900+80;//as he mad profit of Rs.80 by selling x-5 toys in Rs.(y+2).

xy + 2x -5y -10= 900+80;
2x-5y = 90;
2x-5*900/x = 90
2x^2 -4500 = 90x;
x^2 -45x – 2250 = 0;
(x-75)(x+30) = 0;
x = 75 and x =–30, as number of toys cant be negative, initial number of toys were 75.
Initial Cost = 900/75 = Rs.12.

6 numbers add to 21

April 20, 2014 by Sagar 12 Comments

Number Puzzle #89
9 9 9 9 5 5 5 5 3 3 3 3 1 1 1 1 Out of these numbers six numbers add to 21.
Challenge. What are the 6 numbers ?

6 numbers add to 21, Number Puzzle #89

Click here to See Solution

11,1,3,3,3

it is intentionally made tricky

IF 1234=201006

April 11, 2014 by puzzler 6 Comments

Number Puzzle #88
IF 1234=201006, 9155=392016, 4282=401604, 2346=421513, Then 4356=?

Number-Puzzle-#88

5 soldiers in a palace

April 8, 2014 by puzzler 7 Comments

Number Puzzle #87

There is one big palace where 5 soldiers stay. Each soldier has 5 rooms. In each room there are 5 big tigers. Each big tiger has 5 little tigers. Each tiger has 4 legs. How many legs are there in the palace?

Check your answer:-

Click here to See Answers

Answer: There are a total of 3010 legs in the palace.
How?
Number of soldiers = 5 , their legs = 10
Number of big tigers = 5*5*5, their legs = 125*4 = 500
Number of small tigers = 125*5, their legs = 625*4 = 2500
Thus total legs = 3010

$100 and birds puzzle

April 7, 2014 by puzzler 3 Comments

Number Puzzle #86

We have total $100 and we need to buy exactly 100 Birds. The Price list for Birds is as follow:

1) 1 Parrot = $5
2) 1 Crow. = $1
3) 20 Sparrows = $1

But Conditions

You have to spend all $100
You have to buy exact 100 Birds
You have to buy all three types of Birds. So you must have all three kind of birds when you finish buying.

How to spend $100 in this case?

Check your answer:-

Number of Parrots To Buy

Number of Crow To Buy

Number of Sparrows To Buy

Click here to See Solution

19 parrots = 19*5 = 95$
1 crow = 1$
80 sparrows = 4$
100 birds = 100$

If 5 3 2 = 151022

April 5, 2014 by puzzler 9 Comments

Number Puzzle #85
If 5 3 2 = 151022 9 2 4 = 183652 8 6 3 = 482466 5 4 5 = 202541 then 9 5 5 = ?

If 5 3 2 = 151022 9 2 4 = 183652 8 6 3 = 482466 5 4 5 = 202541 then 9 5 5 = ?

Check your answer:-

Click here to see solution

the calculation is like this
9 5 5 =?

9×5 = 45 (first and second)
9×5 = 45 (first and third)
sum of 45+45 =90 and from this deduct center no i.e. 5 =85
hence answer is 454585
Solution is courtesy Jaideep Sandhu, answered in disqus comments

Number Puzzle #84

March 31, 2014 by puzzler 4 Comments

if 532=1561028, 641=244630, 785=564035123 then 821=?

Check your answer:-

Click here to See Solution

here the logic is
R1 = first digit * second digit
R2 = second digit * third digit
R3 = third digit * first digit
so final number is

R1R2R3(R1+R2+R3 – second digit)

for 532=1561028
R1 => 5*3 = 15
R2 = 3*2 = 6
R3 = 2*5 = 10

final number = 15610(15+6+10-3) => 1561028

same logic is true for new two numbers as well

by the same logic for 821
R1 = 8*2 = 16
R2 = 2*1 = 2
R3 = 1*8 = 8

final number 1628(16+2+8-2) => 162824

9 temples with 100 steps

March 26, 2014 by puzzler 4 Comments

Number Puzzle #83

9 temples 100 steps puzzle

A person has some money in his pocket. He visits 9 temples on the way, every temple has 100 steps. he puts Rs.1 on each step while going up and as well as while coming back. On each temple he offers half of the money from his pocket to god, that way his pocket gets empty after 9th temple.
How many Rs. he had initially?

–In Hindi–
Ek aadmi kuch paise leke nikalta hai, raaste me 9 mandir hai ,har mandir me 100 sidiya hai, wo har mandir ki sidiyo pe jate waq 1 ..1..rupia rakhta hai, aate waqt bhi 1..1..rupia rakhta hai,…har mandir me jeeb me bache hove aadhe paise deta hai,….is tarah…jab wo akhri mandir se utarta …to us ke paas ke sab paise khatam ho jate hai,…..sawal ye hai .ke wo kitne paise leke nikalta hai…”

Check your answer:-

Click here to See Solution

Answer: he had a total of Rs.1,46,900 in his pocket initially.
How? We should start from last temple here.
he offered Rs.100 while coming back so he must have offered Rs.100 to the god on 9th temple and offered Rs.100 while going up on the 9th temple. so he had Rs.300 before 9th temple.

similarly before 8th temple: (300+100)*2 + 100 = 900
similarly before 7th temple: (900+100)*2 + 100 = 2100
similarly before 6th temple: (2100+100)*2 + 100 = 4500, we had some error here in calculating, thanks to our readers for correcting us
similarly before 5th temple: (4500+100)*2 + 100 = 9300
similarly before 4th temple: (9300+100)*2 + 100 = 18900
similarly before 3rd temple: (18900+100)*2 + 100 = 38,100
similarly before 2nd temple: (38100+100)*2 + 100 = 76500
similarly before 1st temple: (76500+100)*2 + 100 = 153300

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