A year ago, the ratio of Betty's and Chi's age was 6:7 respectively. Four years hence, this ratio would become 7:8. How old is Betty?
a.34 years
b.29 yeras
c.25 years
d.30 years

• ans: c
  (b-1)/(c-1)=6/7;
  (b-1+4)/(c-1+4)=7/8;
  by solving them we get
  8b-7c=-3
  7b-6c=1
  then solving these eq we get
  c=29
  b=25
• 11 years agoHelpfull: Yes(1) No(2)