Answer:
Amoun of sales Revenue for the first quarter of 2019
 Jan $120,000
Feb ( 120,000*1.05) 126,000
March ( 126,000* 1.05) 132,300
 378,300 
 Cash Receipt schedule for the first quarter of 2019
 Jan Feb March
Jan sales $84,000 24,000 12,000
Feb sales - 88,200 25,200
March sales  -   -  92,610
 84,000  112,200 129,810
Amount of Account Receivable as of MArch 2019
 Feb sale 10%* 126,000 $12,600
March sales( 20%* 132,300) + (10%*132300) 39,690
  52,210
Step-by-step explanation:
cash receipt 
 Jan Sales : Jan 70% * 120,000 = 84,000
 feb 20%* 120,000 = 24,000
 March 10% * 120,000 = 12,000
Feb sales : Feb 70%*126,000 = 88,200
 March 20% * 126,000 = 25,200
 April 10%* 126,000 = 12,600
March sales : March 70%* 132300 = 92,610 
 April 20%*132300 = 26,460
 May 10%*132300 = 13,230