<p>145 300 610 1230
In the above sequence every term after the first is formed by multiplying by x and then adding y, where x and y are positive integers. What is the value of x + y?</p>
<p>im unable to understand the question...
thanks..
i know it might b a simple question but its always good to ask wt u dont knw..
thanks again</p>
<p>The answer is 12. I you multiply each term by 2 and then add 10, you get the following term</p>
<p>Yeah, I got 12, as well. I sort of did a guess-and-check method. If you look at the numbers the previous term is a little more than twice the previous number. So, 145.2 = 290, 300.2 = 600, 610.2 = 1220. It's obvious when you look at the numbers that y = 10 now since 290 + 10 = 300, 600 + 10 = 610, and 1220 + 10 = 1230. </p>
<p>If x = 2 and y = 10, then x + y = 2 + 10 = 12</p>
<p>If you are unable to see the pattern, you can solve it from the following equations:</p>
<p>300 = 145x + y
610 = 300x + y</p>
<p>Subtract eqn(1) from eqn(2), the y variable cancels out:
(610-300) = (300-145)x
310 = 155x
x = 2</p>
<p>Plug x=2 back in one of the original equations to solve for y:
e.g. 300 = (145)(2) + y
300 = 290 + y
y = 10</p>
<p>yea its 12
optimizerdad gives the best explination</p>