price of microchip

I think this is 2.

At the start, the price is $81. After 6 months, it will be 1/3 of its price, or $27. At one year, it will be 1/3 of that, or $9. At 1.5 years, it is $3. At 2 years, it is $1.

I believe two years is the right answer.

Algebraically, it is 1=[81][(1/9)^x], where 1 is the ending price, [81] is the starting price, (1/9) is the fraction of the starting price given x, where x is the amount of time in years. You can see the trend of how it declines after time goes on, and if you plug in for x, you will see that 2 is correct. Luckily, it doesn't take us until 10, 20, etc. to find the answer.

ddm wrote:The price of microchip declines by 67% every 6 months.At this rate approx. how many years will it take for $81 microchip to reach to $1?

A.1.5
B.2
C.3
D.13
E.13.5

Decline of 67% ~ 1/3 the price

81/(3^4) = 1 => 4*6 months = 2 years.

IMO B.

OA-B