How would you work out this maths question?

Hi.


I bought a maths practice paper but theres no answer book so i can't check the answer and how you work it out.





The question is:


The number of gorillas has fallen by 70% in the last ten years. Only about 5000 gorillas are left. About how many gorillas were there ten years earlier?


How would you work this question out?


i tried it but i got a number to the power of 67.





ThanksHow would you work out this maths question?
it says that the number of gorillas has fallen by 70%, so 30% of the original was left which is 5000.





So let n be the original number 10 years earlier.





we have 30% n = 5000 or 0.3n = 5000.


n = 10/3 * 5000 = 50000/3 = 16666.66.... = 16667.





hope this helps!How would you work out this maths question?
%70 of something is lost. That means, you originally had %100 of something. Let us set this something/ gorillas as x.





Test: If we had x numbers of gorillas, and we keep %100, we stay with that same number.


%100 * x = 1x = x





Now, we've lost 70%, which means %30 remains. Follow through with the same logic


%30 * x = .3x





We are given the information that 5000 gorillas are left. So, .7x must be equal to this new value





1: .3x = 5000 ~ [Set in the new value]





2: x = 5000/.3 ~ [Divide by .7 to get x by itself or solve for x]





3: x = 16666.666666666666666666666666667 ~ [Simplify]





4: x = 16667 ~ [Round up, 6%26gt;5]
The number of gorillas remaining today represents 30% of their population 10 years ago.


Let x= the original population of gorillas 10 years ago.


5000= 0.3 x,


solving for x, x=5000/0.3 =16,666.7


Therefore, there were approximately 16,667 gorillas ten years ago.
100%-7%=30%


30% gorillas 5000


100% X


X=No of gorillas 10 years ago=16666
there were 5000*100/(100--70) = 16667 gorillas 10 years earlier.


16667 -- 70% of 16667 = 16667 -- 11667 = 5000
Now you have only 30% of gorillas against the last 10 years.





Total gorillas were in the last 10 yrs = 5000/0.3 = 16667