The sum of the 3 number is 100. The first number is twice the third. The second number is two more than twice the first number. Determine the numbers.

Answer 1

To start a question like this set up some equations using the info given to you.

a+b+c=100 (where a is the first number, b is the second, and c is the third).

a=2c (the first number is twice the third)

b= 2a+2 ( the second is twice the first plus 2)

Then isolate one variable, in this case, the easiest is to get everything in terms of c, once we do that we can figure out what c equals and by proxy what the other 2 numbers equal. (a=2c , and b=2(2c)+2)

Next, substitute into the first equation (2c)+(2(2c)+2)+c=100

simplify, 7c+2=100 (minus 2 from both sides, 7c=98)

c= 14

using this info you can find the other 2 numbers

a= 2(14) a=28

b=2(28)+2 b=58

To check your answer plug the numbers into the original equation, 28+58+14=100,