10. mary's father is four times as old as mary. five years ago he was seven times as old. how old
is each now?

Mary is aged 10 years while her father is 40 years old.

Let:

5 years ago :

We could Equate (1) and (2)

4x - 5 = 7(x - 5)

4x - 5 = 7x - 35

Collect like terms

4x - 7x = - 35 + 5

-3x = - 30

x = 10

Therefore, Mary's age is 10 years and her father's age is 4(10) = 40 years

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Mary is 10 years old, and her father is 40 years old.

Step-by-step explanation:

Let Mary's age = x.

Mary's father is four times as old, so he is 4x.

Five years ago, Mary was x - 5, and her father was 7(x - 5).

Five years ago, Mary's father was 4x - 5.

7(x - 5) = 4x - 5

7x - 35 = 4x - 5

3x = 30

x = 10

4x = 4 * 10 = 40

Mary is 10 years old, and her father is 40 years old.

5x+10 is the correct one

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