The difference of the grandson's age in years and the grandfather's age in years is 77. Therefore, the age of the grandson is 7 years.
How to use equations to find the age?
A grandson's age in months is equal to his grandfather's age in years.
Recall,
12 months = 1 year
Hence,
let
x = age of grandson in month
It is the same age in years for the grandfather.
Therefore,
x = age of grand father in years
The difference of the grandson's age in years and the grandfather's age in years is 77. Therefore,
x - x / 12 = 77
12x - x/12 = 77
11x / 12 = 77
cross multiply
11x = 924
x = 924 / 11
x = 84
Therefore, the grandson age in in years is 84 / 12 = 7 years.
learn more on equation here: https://brainly.com/question/11136531
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