Answer : The number of years it take to widen will be, 650 years.
Explanation :
As we are given that the red see is widening 1.25 centimeters in one year. Now we have to determine the number of years it will take to widen.
As, 1.25 centimeter red sea is widening in 1 year
So, 812.5 centimeter red sea is widening in

Therefore, the number of years it take to widen will be, 650 years.