The ratio of Sarah's age to Keisha's age is 4:5 this year. Keisha was 12 years old 3 years ago. Find the ratio of Sarah's age to Keisha's age 9 years from now.
she will be 36 because 9*12=108/3=36 or in other words the fraction is 12/3 the denominator was three. Now the denominator is 9. in order to get the 9 you had to multiply by 3. so 3*3=9 and 12*3=36 if you have any question feel free to ask:)