Grandma is 64 years old and grandson is 13 years old. How many more years will grandma be four times as old as grandson?

Grandma is 64 years old and grandson is 13 years old. How many more years will grandma be four times as old as grandson?

Let's suppose that after another x years, grandma's age is four times that of her grandson. From the meaning of the question, we can get (13 + x) × 4 = 64 + X & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 52 + 4x = 64 + X & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 3x = 12 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp