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
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January 2021
