She starts with $5.00 a week for 4 weeks so that’s 5*4 = $<<5*4=20.00>>20.00
Then she bumps it up to $10.00 a week for 4 weeks so that’s 10*4 = $<<10*4=40.00>>40.00
After that, she saves $20.00 a week for 4 weeks so that’s 20*4 = $<<20*4=80.00>>80.00
Over 12 weeks she has saved 20+40+80 = $<<20+40+80=140.00>>140.00
#### 140