The age of Mark’s dad is 4 less than twice Mark’s age. The sum of their ages is 95. Find their ages.

Question

how do i solve this

Answer 1

Here's what we know:

d = 2m - 4 (Dad's age is 4 less than twice Mark's)

m + d = 95 (their ages total 95)

 

We have a value for d, so plug it in:

m + 2m - 4 = 95

Simplify:

3m - 4 = 95

Add 4 to both sides:

3m = 99

Divide by 3:

m = 33

 

You should be able to find Mark's dad's age from here.

Answer 2

You need two variables and two equations and then we can solve!

Let M = Mark's age and D = Dad's age. Also "is" means "is equal to".

Now, try to translate this: 

The age of Mark's dad is 4 less than twice Mark's age.

D = 2M-4

The second one is simpler: The sum of their ages is 95. 

D + M = 965 

Then if you rearrange the second equation to say D = 95 - M you can then set the two expressions equal to each other since they both equal D.

D = 2M-4 AND D = 95 - M 

means that 2M-4 = 95 - M 

Can you solve from M from here? 

If not... follow along... Add M to both sides.

Now we have 3M - 4 = 95

Then add 4 to both sides

3M = 99

Divide both sides by 3

M = 33 so Mark is 33

Dad is 95 - 33 = 62 so Dad is 62! 

Hope this helps!