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3 years ago

Roberto is 3 years older than Carolyn. In 7 years the sum of their ages will be 81. How old is Roberto now?

Mathematics

1 answer:

Nuetrik [128]3 years ago

3 0

Answer: 35

the age of Roberto is x (x > 3)(x ∈ N)

because Roberto is 3 years older than Carolyn => the age of Carolyn is x - 3

in 7 years, the age of Roberto is x + 7; the age of Carolyn is x - 3 + 7 = x + 4

because In 7 years the sum of their ages will be 81 =>

x + 7 + x + 4 = 81

⇔ 2x + 11 = 81

⇔ 2x = 70

⇔ x = 70/2 = 35

=> the age of Roberto is 35

Step-by-step explanation:

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