I’m bad at math but not so bad at logic. How about this…

39+91>>>100+60

(Well…it makes sense to me. If it’s not right, how about you try to figure out MY answer!!) :s

Here’s my attempt…

The pattern is (look at the sum and product of each side) : -

A + B -> X + Y

where X + Y = A + B + 10

and A * B = X * Y

Check this…

1’st line

10 * 21 = 6 * 35 = 210

10 + 21 = 31 -> 5 + 35 = 41 (31 + 10)

2’nd line

21 * 34 = 51 * 14 = 714

21 + 35 = 55 -> 51 + 14 = 65 (55 + 10)

So,

39 + 91 -> X + Y

where X + Y = 130 + 10 = 140

and X * Y = 39 * 91 = 3549

This yields a very ugly quadratic equation with even uglier roots…

X^2 - 140X + 3549 = 0

This doesn’t give a very pretty solution though =>

39 + 91 -> 106.7559519 + 33.2440481

So, perhaps my assumptions were wrong… :s

Definitely something to do with factors:

10=2*5
21=3*7

Therefore solution = (2*3) = 6 and (5*7) = 35

21=3*7
34=2*17

Therefore solution = (3*17) = 51 and (7*2) = 14

39=3*13
91=7*13

The only thing is, I don’t know which order to multiply in. So solution could be:

(21,169) or (39,91) [identical]

Unless someone can work out how they picked the ordering.

[quote=“daasgrrl”]Definitely something to do with factors:

10=2*5
21=3*7

Therefore solution = (2*3) = 6 and (5*7) = 35

21=3*7
34=2*17

Therefore solution = (3*17) = 51 and (7*2) = 14

39=3*13
91=7*13

The only thing is, I don’t know which order to multiply in. So solution could be:

(21,169) or (39,91) [identical]

Unless someone can work out how they picked the ordering.[/quote]

:bravo: :bravo: :bravo: :bravo: :bravo: :bravo:

Daasgrrl, well done! I managed to check the solution on the site the puzzle came from, it needs some translation but the numbers are there …

[quote]Okee, hier de oplossing: als we de eerste regel bekijken, zien we dat de getallen 10 en 21 maar op

:bravo: Well done ! Also true for reading Dutch text to verify solution.

I made the answer ‘blue with yellow stripes’. :s

Heh - thanks for the confirmation (I was aware that one could probably trace back the URL, but I didn’t try it). Although it wouldn’t pass as a true logic puzzle IMO unless there was some designated pattern for choosing which factors to multiply…OK, I’m a geek :help: