Answer :
So total she saved 22+39 so far. That's 61 dollars in total (22+39=20+41=61).
She needs 100 dollars total, but she has 61 already, so she only needs 100-61=39 more: she needs 39 dollars more.
She needs 100 dollars total, but she has 61 already, so she only needs 100-61=39 more: she needs 39 dollars more.
You add 22 to 39 which is 61. Then you do 100-61 which is 39. So Janet needs $39