Answer :

Good.
She wants to pay 20% down:
=  20 / 100  * 840    =  168.

The remainder =  840 - 168  =      672

She wants to pay the remainder in six equal payments =  672 / 6 =  112.

= $112          (B).
20/100 x 840=$168 is the amount of money that she has to pay right away
and the rest = 840-168=$676
she has to pay in 6 months so $676/6= 112.6666
=$112.67 per month
->B