Find the age now

Sophie is 6 years older than Betty. In 3 years' time Sophie will be twice as old as Betty. How old is Sophie now?

---

b = Betty’s age now
b + 6 = Sophie’s age now

b + 3 = Betty in 3 years
b + 9 = Sophie in 3 years {added 3 onto current ages}

b + 9 = 2(b + 3) {in three years, Sophie will be twice Betty}
b + 9 = 2b + 6 {used distributive property}
b = 3 {subtracted b and 6 from each side}
b + 6 = 9 {substituted 3, in for b, into b + 6}

Sophie is 9 now

Ask the House

Leave a Tip