# Math puzzles questions?

• May 21st 2014, 10:15 PM
amrithaa
Math puzzles questions?
1. What number should replace the question mark?
http://www.treeknox.com/general/puzz...questions1.jpg
2.What number should replace the question mark?
http://www.treeknox.com/general/puzz...questions3.jpg

3.What number should replace the question mark?
http://www.treeknox.com/general/puzz...questions4.jpg
4.What number should replace the question mark?
http://www.treeknox.com/general/puzz...questions5.jpg
5.What number should replace the question mark?
http://www.treeknox.com/general/puzz...questions8.jpg

Regards,
• Aug 2nd 2014, 03:20 PM
Soroban
Re: Math puzzles questions?
Hello, amrithaa!

Quote:

2. What number should replace the question mark?

. . $\displaystyle \boxed{\begin{array}{ccccc} .&.&.&14&. \\ .&22&.&.&. \\ .&.&.&34&. \\ 41&.&.&.&. \\ .&.&53&.&? \end{array}}$

Spoiler:

Each number indicates its row and column.
The "?" is in the 5th row, 5th column.
Its number is 55.

Quote:

3. What number should replace the question mark?

. . $\displaystyle \boxed{\begin{array}{cc}5 \\ 8\quad 5 \\ 1\quad 7 \end{array}} \qquad \boxed{\begin{array}{c} 4 \\ 7\quad 6 \\ 1\quad 9 \end{array}} \qquad \boxed{\begin{array}{c} ? \\ 9\quad 1 \\ 1\quad 3 \end{array}}$

Spoiler:

The second row divided by the third row equals the top row.

$\displaystyle 85 \div 17 \:=\:5,\quad 76 \div 19 \:=\:4,\quad 91\div 13 \:=\:{\color{red}7}$

Quote:

4. What number should replace the question mark?

$\displaystyle \boxed{\begin{array}{c|c|c} 47&55&63 \end{array}} \quad \boxed{\begin{array}{c|c|c}85&92&99 \end{array}} \qquad \boxed{\begin{array}{c|c|c} 73&\;?\;&25 \end{array}}$

Spoiler:

The middle number is the average of the other two.

$\displaystyle \frac{47+63}{2} \:=\:55,\quad \frac{85+99}{2} \:=\:92,\quad \frac{73+25}{2} \:=\:{\color{red}49}$

• Aug 3rd 2014, 05:36 AM
SheekhKebab
Re: Math puzzles questions?
Quote:

Originally Posted by amrithaa
1. What number should replace the question mark?
http://www.treeknox.com/general/puzz...questions1.jpg

Each row is 8 times the immediate row above. 9X8=72. 72X8=576. bottom row 576X8=4608. So there will be 0 in place of question mark in the lowest row.
• Aug 3rd 2014, 06:01 AM
SheekhKebab
Re: Math puzzles questions?
Quote:

Originally Posted by amrithaa

5.What number should replace the question mark?
http://www.treeknox.com/general/puzz...questions8.jpg

Each two digit number is a sum of digits of one three digit number. 2+6+8=16; 3+5+9=17; 2+6+3=11; and therefore the number in place of question mark is 5+1+6=12.
• Aug 3rd 2014, 06:54 AM
Soroban
Re: Math puzzles questions?
Hello again, amrithaa!

Quote:

5. What number should replace the question mark?

. . $\displaystyle \boxed{\begin{array}{c} 268 \qquad 11 \\ \\[-3mm] 17 \qquad\quad 259 \\ ? \\ 16 \qquad\quad 516 \\ \\[-4mm] 263 \end{array}}$

Spoiler:

Each 2-digit number is the digit-sum of a 3-digit number.

. . $\displaystyle \begin{array}{ccc}263 & \to & 11 \\ 268 & \to & 16 \\ 359 & \to & 17 \\ 516 & \to & {\color{red}12} \end{array}$
• Aug 6th 2014, 07:40 PM
dennydengler
Re: Math puzzles questions?
Lol 4 is not as bad: the number in the middle is the average of the 2 others on the sides.
• Aug 6th 2014, 07:41 PM
dennydengler
Re: Math puzzles questions?
3. 5=85/17, 4=76/19 so ?=91/13