Last night I spent the evening with some of my family who live nearby. I cooked a big pot of chicken and sausage gumbo, and we had a fantastic time catching up.
As I sat down on the couch after devouring a sugar cookie for dessert, my uncle handed me one of those big legal note pads. On it was a brain teaser that a friend had sent him via email. In my sugared brain fog, I worked through it and thought I would share it with you.
Look at the following series of numbers and determine which number goes in place of the question mark.
2,3,10
3,4,21
4,5,36
5,6,55
6,7, ?
You can post your answers in the comments below, and then check the solution to see if you were correct.
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About the author, Erin Matlock
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189 Comments On This Post
78
78 its easy :D
78
You take the product of the first two numbers and add it to the square of the first number to equal the last number. For example, 2,3,10:
you multiply 2 by 3 to equal 6. Then you add the 6 to the square of the first number which in this case would be 4 (2 squared).
79
78
a, b, c
c = (a + b) x a
6 + 7 = 13
13 x 6 = 78
2,3,10
3,4,21
4,5,36
5,6,55
6,7, ?78
78
2×5=10
5+2=7
3×7=21
7+2=9
9×4=36
9+2=11
11×5=55
11+2=13
13×6=78
I think Mandy’s remark about adding 4 to the sequence is by example:
21 – 10 = 11. Add 11 + 4 to 21 and you get 36.