SOLUTION: Mary is twice as old as Susan and three years older than John. The sum of their ages is 32. How old is Susan?

Question 260697: Mary is twice as old as Susan and three years older than John. The sum of their
ages is 32. How old is Susan?
Answer by drk(1908) (Show Source): You can put this solution on YOUR website!
m = mary
s = susan
J = john
------
(i) m = 2s
(ii) m = j + 3
(iii) m+s+j = 32
step 1 - set (i) = (ii) and solve for j. We get
(iv) 2s = j + 3
(v) j = 2s-3
step - 2 rewrite m and j in terms of s using (i) and (v). We get
(vi) 2s + s + 2s -3 = 32
step 3 - solve for s. WE get
(vii) 5s - 3 = 32
add 3 to get
(viii) 5s = 35
divide by 5 to get
(ix) s = 7
So, susan is 7.
RELATED QUESTIONS
Mary is now three as old as susan. Three years ago, the sum of their ages was 22. How old (answered by robertb)

Mary is three times as old as susan. Two years ago, the sum of their ages was twenty. How (answered by ikleyn)

Susan is twice as old as Mary. In five years, their ages will total 49. How old is each... (answered by stanbon)

lisa is six years older than susan,jessie is 5 years older than lisa ,and the total of... (answered by ankor@dixie-net.com)

John is 12 years older than Susan. The sum of their age is 42. How old is each? (answered by TimothyLamb)

john is 10 years older than susan. five years ago, the sum of their ages was 34. how old... (answered by josgarithmetic)

Kate is 5 years younger than Susan, and Melinda is 2 years older than Susan. If the sum... (answered by math_helper)

Susan is six years older than Mary. She is twicw as old as Mary. How old is each... (answered by nerdybill)

susan is 3 years older than tom. two years ago susan was twice as old as tom. find their... (answered by lwsshak3)