Question

Kim's age is three times that of her sister's age. When you add Kim's age to her sister's age, you get 40. How old is each sister? (a) Write an equation that represents the situation. Explain any variable used. (b) Solve the equation from part (a). Show your work. State your solution as a complete sentence.

Please help I do not understand how to do this. Thank you

Answer 1

When solving a problem like this you will need to break down the equation. The answer is actually really simple and easy.

For Kim's age we will use X as the variable. For her sister we will use Y.

y*3=x and X+Y=40 and that will get us our answer.

Now we are going to break it down. Kim is three times the age of her sister. So what number under 40 can be evenly distributed into 3 parts since we need to find a number three times greater than another number that can be added one time to itself to equal 40.

The answer to that question would be x=10.

Which means her younger sister is going to be 10

So taking that and plugging it into our equation we will get the following;

10*3(y*3) = (x)30

Which now means Kim's age is 30.

Now we check to make sure. Does 30 + 10 = 40? If so then that's your answer explained and in depth.