+0

im stuck in this koobits !

0
417
5

Find the sum of the following series by pairing two numbers to make ten(s). 1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19

Guest Nov 20, 2015

#2
+18948
+15

Find the sum of the following series by pairing two numbers to make ten(s).

1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19

$$\begin{array}{rcrcrcrcrcrcrcrcrcrcr} \hline \hline 1 &+& 3 &+& 5 &+& 7 &+& 9 &+& 11 &+& 13 &+& 15 &+& 17 &+& 19 & \\ \hline \hline 1 & & & & & & & & & & & & & & & & &+& 19 & =& 20 \\ \hline & & 3 & & & & & & & & & & & & &+& 17 & & & =& 20 \\ \hline & & & & 5 & & & & & & & & &+& 15 & & & & & =& 20 \\ \hline & & & & & & 7 & & & & &+& 13 & & & & & & & =& 20 \\ \hline & & & & & & & & 9 &+& 11 & & & & & & & & & =& 20 \\ \hline \hline & & & & & & & & & & & & & & & & & & & =& 100\\ \hline \hline \end{array}$$

( 1 + 19 ) + ( 3 + 17 ) + ( 5 + 15 ) + ( 7 + 13 ) + ( 9 + 11 ) = 20 + 20 + 20 + 20 + 20 = 100

heureka  Nov 20, 2015
edited by heureka  Nov 20, 2015
edited by heureka  Nov 20, 2015
Sort:

#1
+5

(1+9) + (3+7) + (5+15) + (7+13) + (11+19)

10 + 10 + 20 + 20 + 30  = 90

Guest Nov 20, 2015
#2
+18948
+15

Find the sum of the following series by pairing two numbers to make ten(s).

1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19

$$\begin{array}{rcrcrcrcrcrcrcrcrcrcr} \hline \hline 1 &+& 3 &+& 5 &+& 7 &+& 9 &+& 11 &+& 13 &+& 15 &+& 17 &+& 19 & \\ \hline \hline 1 & & & & & & & & & & & & & & & & &+& 19 & =& 20 \\ \hline & & 3 & & & & & & & & & & & & &+& 17 & & & =& 20 \\ \hline & & & & 5 & & & & & & & & &+& 15 & & & & & =& 20 \\ \hline & & & & & & 7 & & & & &+& 13 & & & & & & & =& 20 \\ \hline & & & & & & & & 9 &+& 11 & & & & & & & & & =& 20 \\ \hline \hline & & & & & & & & & & & & & & & & & & & =& 100\\ \hline \hline \end{array}$$

( 1 + 19 ) + ( 3 + 17 ) + ( 5 + 15 ) + ( 7 + 13 ) + ( 9 + 11 ) = 20 + 20 + 20 + 20 + 20 = 100

heureka  Nov 20, 2015
edited by heureka  Nov 20, 2015
edited by heureka  Nov 20, 2015
#3
+91779
0

What a fabulous diagram Heureka,

Melody  Nov 20, 2015
#4
0

Two great answers, but one of them must be wrong.

The first says 90, the second 100.

Guest Nov 20, 2015
#5
0

Yep One of them is wrong....and it's my answer    the answer is 100...I made a typo. The 4th term in my sequence should read (17+13)    NOT   (7 +13)

Guest Nov 21, 2015

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