Rita's mother is 4 times as old as she is. her grandmother is twice as old as her mother. if the sum of their age is 194, how old are rita, her mother, and her grandmother?

R=rita's age
m=mother's age
g=grandmother's age

mother is 4 times as old as rita
m=4r

grandmother is 2 times as old as mother
g=2m

sum is 104

r+m+g=104
subsitute 4r for m and 2m for g
r+4r+2m=104
subsitute 4r for m
r+4r+2(4r)=104
r+4r+8r=104
13r=104
divide both sides by 13
r=8
4r=m=32
8r=2m=g=64

rita is 8
mother is 32
grandmother is 64