Wednesday, April 16, 2008

Hi 2e2,

Here's some puzzles for you to solve! Hint.. all can be solved using algebra!

LEVEL 1

What number gives the same results when it is added to 1.5 as when it is multiplied by 1.5?

LEVEL 2

Peter picked one pebble more than Paul. Pat picked one pebble more than Pam. Peter and Paul picked 10 more pebbles than Pam and Pat. Peter, Paul, Pam and Pat picked 60 pebbles in total. How many pebbles did Peter pick?

LEVEL 3

A certain number consists of two digits. The number is equal to five times the sum of its digits. If you add 9 to the number, its order of its digit is reversed. What is the number?

Alright, that's all for today. Once again, well done 2e2, for completing your homework on time! Keep up the good job!

PS: Please post your answers [and workings if any] in the comments session. Keep the blog going!

Miss Gina

10 Comments:

Blogger Frits said...

1st question;

3+1.5 = 4.5
3*1.5 = 4.5

Ans : 3

1st comment =D

April 17, 2008 at 3:17 PM  
Blogger Frits said...

This comment has been removed by the author.

April 17, 2008 at 3:55 PM  
Blogger Frits said...

Question 3;

By trial and error method

12+9 = 21
23+9 = 32
34+9 = 43
45+9 = 54
56+9 = 65
.......

There's a pattern there.

45+9 = 54 -- Reversed
(4+5)*5 = 9*5 = 45

Answer : 45

April 17, 2008 at 3:56 PM  
Blogger Miss Gina said...

Well Done Frits !!!

Correct answer for both questions.

Now, who can solve the same two questions using algebra?

Hint: Let x be .....

April 17, 2008 at 9:09 PM  
Blogger Nk sMiLe said...

This comment has been removed by the author.

April 18, 2008 at 4:38 PM  
Blogger Nk sMiLe said...

This comment has been removed by the author.

April 18, 2008 at 4:59 PM  
Blogger Nk sMiLe said...

let's x be the number, y be the munber of result.
x+1.5=y ---1
1.5x=y ---2
subts 2 into 1
x+1.5=1.5x
1.5=1.5x-x
1.5=0.5x
3=x
Ans: the number is 3

KoUn=D

April 18, 2008 at 5:01 PM  
Blogger Mich. said...

question 1 :
let a be the unknown number ,
let b be the unknown result .
a + 1.5 = b ---> 1
a x 1.5 = b ---> 2
1.5a = b ---> 3
from 3 into 1
a + 1.5 = 1.5a
1.5 = 1.5a - a
1.5 = 0.5a
a = 3

unknown number : 3

April 18, 2008 at 5:02 PM  
Blogger Mich. said...

question 2 :
let a be the number of pebbles Paul collected .
let b be the number of pebbles Pam collected .

Paul ---> a
Peter ---> a + 1
Pam ---> b
Pat ---> b + 1
Peter and Paul ---> b + b + 1 + 10
= 2b + 11
2b + 11 = a + a + 1
2b + 11 = 2a + 1
2b + 11 + b + b + 1 = 4b + 12
4b + 12 = 60 pebbles
4b = 60 - 12
4b = 48
b = 12 pebbles
Pam ---> 12 pebbles
Pat ---> 12 + 1 = 13 pebbles
Peter and Paul ---> 60 - 13 - 12
= 35 pebbles
2b + 11 = 2a + 1 = 35
2a + 1 = 35
2a = 35 - 1
2a = 34
a = 17
Paul ---> 17 pebbles
Peter ---> 17 + 1 = 18 pebbles
Peter picked up 18 pebbles .

April 18, 2008 at 5:17 PM  
Blogger Mich. said...

question 3 :
let x be digit 1 ,
let y be digit 2 ,
let n be the unknown number .

n = xy ---> 1
n = 5 ( x + y ) ---> 2
n = 5x + 5y ---> 3
n + 9 = yx ---> 4

let x be 1 ,
let y be 2 .
n = 12
n = 5 ( 1 + 2 )
n = 5 + 10
n = 15 - wrong answer .

let x be 2 ,
let y be 3 .
n = 23
n = 5 ( 2 + 3 )
n = 10 + 15
n = 25 - wrong answer .

let x be 3 ,
let y be 4 .
n = 34
n = 5 ( 3 + 4 )
n = 15 + 20
n = 35 - wrong answer .

let x be 4 ,
let y be 5 .
n = 45
n = 5 ( 4 + 5 )
n = 20 + 25
n = 45 - correct answer
45 + 9 = 54

unknown number : 45

April 18, 2008 at 5:38 PM  

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