Hi i have a kind of weird situation... my professor assigned review questions along with the answers and i was wondering if you could explain how he got each answer. More specifically the budgeted beginning inventory (900) and (1460)

Problem 3: Direct Materials Budget (based on Ex 20-4)
Elder Corporation set their production budget in units for the next three months:
			April	May	June
		Units	7,000	7,300	8,400
Each unit requires 2 pounds of direct material at a cost of $2.70 per pound. The company's policy is to end each month with an inventory of direct materials equal to 10% of the next month's direct material requirements. At the beginning of April, 900 pounds of material are on hand.
	Prepare a Direct Materials Budget for April and May.
	Direct Materials Budget					April	May
	Budgeted production (units)					7,000	7,300
	Materials requirements per unit (pounds)					x 2	x 2
	Materials needed (pounds)					14,000	14,600
	Desired ending inventory*					1,460	1,680
	Total needed					15,460	16,280
	Budgeted beginning inventory					(900)	(1,460)
	Materials to be purchased					14,560	14,820
	Cost per unit of materials					x $2.70	x $2.70
	Total materials cost					$39,312	$40,014

*Calculation for Budgeted ending inventory based on 10% of next months production. Calculation for April 7,300 x 10% x 2 pounds = 1,460 pounds and for May 8,400 x 10% x 2 pounds = 1,680 pounds.