Working Backwards:

In the 1980's the Northen White Rhinoceros population decreased by 485 from what it was in the 1970s. By the 1990s the population increased 2 more than twice the population in the 1970s By the 2000s the population dropped 25 rhinoceroes to about 7 today what was the population in the 1970s

call the population in the seventies X

then in the eighties it was (X-485)
in the nineties it was 2+2X +(X-485) {I am taking the English here literally that the population "INCREASED" an amount 2+2X over what it was in the eighties. I hope you do not have a typo and it should be "INCREASED TO"}
in 2000s 2+2X +X - 485 -25 = 7
so there is your equation to solve for X

500

(7+25-2)/2+485=500

its 300

To find the population of the Northen White Rhinoceros in the 1970s, you can use the method of working backwards.

Let's break down the information given:

1. In the 1980s, the population decreased by 485 from what it was in the 1970s.

2. By the 1990s, the population increased 2 more than twice the population in the 1970s.

3. By the 2000s, the population dropped 25 rhinoceroses to about 7 today.

To work backwards, we'll start with the current population and move step by step back in time.

1. Given that the population today is about 7, we know that in the 2000s, it dropped 25 rhinoceroses. So, in the 2000s, the population would have been 7 + 25 = 32.

2. In the 1990s, the population increased 2 more than twice the population in the 1970s. Let's call the population in the 1970s "x." So, in the 1990s, the population would have been 2 * x + 2 = 32. Solving this equation, we get 2x = 30, which gives us x = 15.

3. Finally, in the 1980s, the population decreased by 485 from what it was in the 1970s. So, in the 1980s, the population would have been 15 + 485 = 500.

Therefore, the population of the Northen White Rhinoceros in the 1970s was 500.