Khan Academy Math

Question

Ben is 3 times as old as Daniel and is also 4 years older than Daniel

Answer 1

Hi Kayla, I'm happy to help you with this. Let's give Ben and Daniel variables (b & d) and put this into two equations to solve for both their ages:

Ben is 3 times as old as Daniel: b = 3d

Ben is 4 years older than Daniel: b = d + 4

To solve for the variables, we need to either use substitution or elimination. Let's use substitution for this one. Because b is equal to both 3d and d + 4, you can set the two equations to each other:

3d = d + 4

2d = 4

d = 2

So, Daniel is 2. Plug 2 in for "d" in either equation to find Ben's age.

b = 2 + 4 ...or... b = 3(2)

So, Ben is 6.

I hope this helps!