Question #b9e5a

2 Answers

The Father is now 40 and Mary is 10.

Explanation:

Let us say the current Mary is M and her current father is F.

1) In the present:

F=4M

Mary’s father is four times as old as Mary.

2) Using the terms above, the equation of their age 5 years ago is this:

F5=7(M5)

The father is 5 years younger and is 7 times older than Mary was 5 years ago.

3) Remove the brackets from the previous equation, simplify it and bring it into the terms of F.

i) F5=7M35

ii) F=7M30

4) Piece it all together.

7M30=4M

3M30=0

3M=30

M=10

We already know that F=4M, and we just worked out that F also =7M30. This means 4M and 7M30 is the same. After working it all out, we see M=10.

5) Double check by substituting.

M=10

F=4M=40

F5=35

M5=5

5×7=35

It all works out...

6) All Done! I hope I helped.

Jul 29, 2017

She is 10 now and he is 40

Explanation:

There are two people: Mary and her Father

and two periods of time: present and 5 years ago.

Write an expression for each person for each period of time:

Mary is younger, so let her present age be x
Her father is 4 times older, so his present age is 4x

Five years ago, they were both younger by 5 years

Mary's age was x5
Her father was 4x5

However, 5 years ago, he was 7 times as old as she was.

Write this as an equation.

7(x5)=4x5

7x35=4x5

7x4x=355

3x=10

x=10

She is 10 now and he is 40

5 years ago .... She was 5 and he was 35

7×5=35