Help - Stupid Maths question....can anyone solve?

[Northdad]

Either I'm being stupid....or the answer requires trial and error and does not require mathematical logic - could be either! It's question 39 e. of Group 2 NLC paper from 2011

Many thanks in advance!

http://www.godolphinandlatymer.com/_fil ... s_2011.pdf

[J50]

The former.

[IronMikeTyson]

It's 13.

# means add the 2 numbers and then add 5 ?

[stevew61]

Add the two given numbers and then add 5?

[Northdad]

Thanks for the quick reply. Correct, I was being stupid. Let's hope DD is cleverer....

[Proud_Dad]

I think its just trial and error and spotting patterns rather than using any foolproof method.

I found (d) the hardest and eventually realised it was half the first number plus the second so thought the answer was 7. Is that right?

[BucksBornNBred]

I don't think it is trial and error. For questions c-e it says to "use the examples" and in each example you always add the two given numbers together and then find the "missing" calculculation/number.

[Guest55]

Not in all the question parts BucksBornNBred....

However, you can eliminate multiplication and division by looking at the numbers - there are odd numbers and no fractions so no division, there is a '9' so any multiplication would be too big.

It has to be addition ...

[BucksBornNBred]

We are going to have to agree to disagree on this Guest55 This would make a good NVR question as it just looks like patterns to me!

a and b both state you add the numbers together and then do another calculation. The question says to take the examples and use them to calculate c-e, which to me points to the fact that the first two given numbers also have to be added together and another calculation found to link them together, as per the examples.

[Proud_Dad]

We are going to have to agree to disagree on this Guest55 This would make a good NVR question as it just looks like patterns to me!

a and b both state you add the numbers together and then do another calculation. The question says to take the examples and use them to calculate c-e, which to me points to the fact that the first two given numbers also have to be added together and another calculation found to link them together, as per the examples.

I took "the examples" to mean the 3 examples within c-e, rather than what was in parts a and b.