( )+( )+( )=30 fill the brackets with these numbers and you can also repeat the numbers 1,3,5,7,9,11,13,15

Question

Just want the answer

Answer 1

1,3,5,7,9,11,13, and 15

()+()+()=30

If you can only use three of the numbers this is impossible.

They are all odd numbers.

odd+odd+odd=odd, not even and 30 is even

odd+odd=even and even+odd=odd

However,....

If you use some tricks like the following you can do this...

(15)+(5)+(11-1)=30

(3!)+(9)+(15)=30  (3!=3*2*1=6)

(11+1)+(3)+(15)=30

use the 9 upside down !!!

(6)+(9)+(15)=30

(3+7)+(9+1)+(15-5)=30

and so on...

Answer 2

We know that 15 + 15  gives us 30, which is the result we need. But wee need to add 3 numbers.  Lets start with 15, chose any number in the set as our second number, and solve for the last number by setting up equations.

 

15 + 11 + n = 30

 

n = 30 - 26

n = 4

 

This will not work because 4 is not a number that is in the given set.  We try another number.

 

15 + 13 + n = 30

 

n = 30 - 28

n = 2

 

 

Not this time.

 

15 + 9 + n = 30

 

n = 30 - 24

n = 6

 

 

Keep trying.

 

15 + 7 + n = 30

 

n = 30 - 22

n = 8

 

 

Don't give up.

 

15 + 5 + n = 30

 

n = 30 - 20

n = 10

 

 

Almost there.

 

15 + 3 + n = 30

 

n = 30 - 18

n = 12

 

 

15 + 1 + n = 30

 

n = 30 - 16

n = 14

 

We used every number in this strategy.  Clearly, this did not work out.  Next, we use a different approach.  We guess.

 

 

Going back to the last step:

 

15 + 1 + n = 30
 
n = 30 - 16
n = 14

 

Half of 14 is 7.  This number is in the given set.  We write the number sentence as

 

 

2(7) + (15) + (1) = 30

 

14 + 15 + 1 = 30

 

So we can add 1, 7, and 15 together.  We just multiply 7 by 2.