Ralph is 3 times as old as Sara. In 4 years, Ralph will be only twice as old as Sara will be then. Find Ralph's age now. If x represents Sarah's age now, which of the following expressions represents Ralph's age in four years?

Question

Ralph is 3 times as old as Sara. In 4 years, Ralph will be only twice as old as Sara will be then. Find Ralph's age now.  If x represents Sarah's age now, which of the following expressions represents Ralph's age in four years?

thesmartone · Answer

Ralph is R 
Sara is S

thesmartone · Answer

R=3S is the first equation.

anonymous · Answer

Ralph is 3 times as old as Sara. In 4 years, Ralph will be only twice as old as Sara will be then. Find Ralph's age now.

If x represents Sarah's age now, which of the following expressions represents Ralph's age in four years?



3x

6x

2x + 4

3x + 4

thesmartone · Answer

R+4=2(S+4) is the second equation

thesmartone · Answer

Remember that R and S is their current age.

thesmartone · Answer

so let us distribute the second equation
it will become R+4=2S+8

thesmartone · Answer

Now lets plug in the first equation in to the second one

thesmartone · Answer

3S+4=2S+8
S=4

thesmartone · Answer

R=3S
R=3(4)
R=12

thesmartone · Answer

It wants Ralphs age in 4 years so R+4 which is 12+4=16

thesmartone · Answer

So for your answer choices plug in x=4 because that is Sara's age and see which one gives you 16.

thesmartone · Answer

It should be 3(4)+4=16
So the answer is 3x+4