Question

When David was asked how old he was, he said " I'm three times younger than my dad, but twice as old as Rebecca. " Then little Rebecca ran up to him and declared "i am 30 years younger than my dad". How old is David

Answer 1

Using a system of equations, it is found that David is 12 years old.

What is a system of equations?

A system of equations is when two or more variables are related, and equations are built to find the values of each variable.

The variables are given as follows:

• Variable x: David's age.

• Variable y: Dad's age.

• Variable z: Rebecca's age.

David is three times younger than the dad and twice as old as Rebecca, then:

• x = y/3 -> y = 3x.

• x = 2z.

Rebecca is 30 years younger than the dad, hence:

z = y - 30.

Then, since x = 2z and z = y - 30 and y = 3x, we solve for x to find David's age.

x = 2(y - 30)

x = 2(3x - 30)

x = 6x - 60

5x = 60

x = 60/5

x = 12.

David is 12 years old.

More can be learned about a system of equations at brainly.com/question/24342899

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