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Aerin's friend Fritz gives her a riddle to solve about the ages of the people in his family. There are 5 people in Fritz's family: Mom, Dad, his sisters Adele and Erika, and Fritz. Here are the clues to the puzzle. 1) Mom is 8 years younger than Dad. 2) Dad is 2 times as old as Fritz. 3) Adele is 4 years old. 4) Fritz's age plus Adele's age equals Erika's age. 5) Mom was 24 when Erika was born. 6) In 9 years, Mom will be twice as old as Erika will be. All the ages are whole numbers. Aerin decides to use variable for the unknown ages and write equations to express the information. M

Sagot :

Answer:

Dad = 47, Mom = 39, Fritz = 11, Erika = 15 and Adele = 4

Step-by-step explanation:

Let M = Mom's age, D = Dad's age, F = Fritz's age, A = Adele's age and E = Erika's age.

Given that

1) Mom is 8 years younger than Dad, we have D = M + 8   (1)

2) Dad is 2 times as old as Fritz. D = 2F   (2)

3) Adele is 4 years old. A = 4     (3)

4) Fritz's age plus Adele's age equals Erika's age. F + A = E   (4)

5) Mom was 24 when Erika was born. M = E + 24    (5)

6) In 9 years, Mom will be twice as old as Erika will be. M + 9 = 2(E + 9)   (6)

Substituting (5) into (6), we have

E + 24 + 9 = 2(E + 9)

E + 33 = 2E + 18

subtracting E from both sides, we have

2E - E + 18 = 33 + E - E

E + 18 = 33

subtracting 18 from both sides, we have

E + 18 - 18 = 33 - 18

E = 15

M = 15 + 24 = 15 + 24 = 39

From (4) F = E - A = 15 - 4 = 11

From (1) D = M + 8 = 39 + 8 = 47

So, their ages are Dad = 47, Mom = 39, Fritz = 11, Erika = 15 and Adele = 4