A sequence of numbers is called a Fibonacci-type sequence if each number (after for the first two) is the sum of the two numbers which precede it. For example, 1, 1, 2, 3, 5, 8 ... is a Fibonacci- type sequence. If 1985, x, y, 200 are four consecutive terms in a Fibonacci-type sequence, then x equals...

Question

I don't know what they want. Please help.

Answer 1

y = 1985 + x
200 = x + y

so

200 = x + (1985+x)

back to you :)

Answer 2

By the way I suspect you mean 2000 not 200

Answer 3

y = 1985+x
200 = x+y
Eliminate y and we have

1985+x = 200-x
2x = -1785
x = -892.5

and the numbers are

1985, -892.5, 1092.5, 200

Answer 4

It would help if that last date were odd :)

Answer 5

It is 2000. But thanks!