Junior Cycle Mathematics ALGEBRA - Equations from Words: John is three times as old as Ma

Question

John is three times as old as Mary. Mary's age in years is represented by x. Select one expression from A, B, C, D and E below which represents John's age in years.

Mary's age is x and John's age is three times that i.e. So B is the correct answer.

Select one expression from A, B, C, D and E above which represents John's age in 3 years time.

Currently, John's age is 3x, so in three years his age will be 3x + 3. This is expression C.

Select one expression from A, B, C, D and E which represents Mary's age in 3 years time.

Currently, Mary's age is x, so in three years here will be x + 3. This is expression A.

In three years time, John's age added to Mary's age will give a total of 26 years. Write down an equation in x to represent this statement.

(John's age in 3 years) + (Mary's age in 3 years) = 26
(3x + 3) + (x + 3) = 26
4x + 6 = 26

Solve your equation to find Mary's present age.

4x + 6 = 26
4x = 20
x = 5

So Mary is 5 years old. We can verify this against the problem statement in part (iv).

John is three times as old as Mary - Junior Cycle Mathematics - Question 10 - 2014

Worked Solution & Example Answer:John is three times as old as Mary - Junior Cycle Mathematics - Question 10 - 2014

Select one expression from A, B, C, D and E below which represents John's age in years.

Select one expression from A, B, C, D and E above which represents John's age in 3 years’ time.

Select one expression from A, B, C, D and E which represents Mary's age in 3 years’ time.

In three years, John's age added to Mary's age will give a total of 26 years. Write down an equation in x to represent this statement.

Solve your equation to find Mary's present age.

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