if the girls are "g" and the boys are "b"
g + b = 13
b = g + 7 <--- 7 more boys than girls

Answer:
The mother is 30 and the daughter is 6
Step-by-step explanation:
When solving for this, you can derive the equations
x=5y and x+6= 3(y+6)
x= mother and y= Daughter
Solve the equations by substituting the first equation into the places of x in the second equation to get the value of x. Next, pug in the value of x and solve for y.
Combine like terms in the first set and get
41.6x +52/2.6x + 13
I got 16x + 4