11 Plus Exams Forum

We have been given some examples to work through and I can do all of them except this one:-

( 21 [ 30 ] 1 ) ( 20 [ 11 ] 10 ) ( 16 [ ___ ] 2 )

The answer given is 17 - but why? DS did some wonderfully convoluted method and came up with the answer 17 (before I had checked the answers) but is now unable to remember exactly what he did! Was it just a lucky guess on his part?

It's beginning to drive me mad(der)

There are two steps involved here.
step 1 : divide first number by second number.
step 2 : add 9 to the result of step 1.

first set :
21 divided by 1 = 21, 21 +9 = 30

second set :
20 divided by 10 = 2, 2 +9 = 11

so, following this method :
16 divided by 2 = 8 , 8 +9 =17

Hope this helps !!

I believe it is :

Divide the first number on the left of the brackets by the one on the right of the brackets - then add 9.

So - 16 divided by 2 is 8, add 9 makes 17.


Snap - our posts coincided!

Thanks guys