Answer:
Step-by-step explanation:
first step
let's create the equation word problem
let's solve
let my mother's and sister's age be x and y respectively
according to the first condition,x=4y....(I)
according to the 2nd condition,x+5=2(y+5×2).....(ii)
so the system of linear equations is
x=4y
x+5=2(y+5×2)
gets from the second equation
x+5=2(y+10)
x+5=2y+20
4y+5=2y+20 (as x=4y)
2y=15
y=7.5
so the age of mother is
x=4.(7.5)
x=30