Question

To get the next number in a sequence you double the previous number and subtract two. The

fifth number in the sequence is 50. Find the first number.​

Answer 1

Answer:

Let the First number in the sequence be x.

Second number = 2x-2

Third number = 2(2x-2) -2 = 4x-4-2 = 4x-6

Fourth number = 2(4x-6)-2 = 8x-12-2 = 8x-14

Fifth Number = 2(8x-14) - 2 = 16x-28-2 = 16x-30

But the fifth number is 50. or 16x-30 = 50. or 16x = 80, x = 80/16 = 5. So the first number is 50.