Question 971814
we have two equations in two unknowns, let x be the girl and y be her mother, then
x = y/3
x + 3 = (2/5) * (y + 3)
substitute for x in second equation
y/3 + 3 = (2/5) * (y + 3)
y/3 + 3 = 2y/5 + 6/5
multiply both sides of = by 15
5y + 45 = 6y + 18
y = 27 and x = 9
the girl is 9 and her mother is 27
check the answer by substituting for x and y in the second equation
9 + 3 = 2/5 * (27 + 3)
12 = (2/5) * 30
12 = 12
answer checks