$273 ,000 being the equal installments for all the three years
Explanation:
I year interest = $ 630,000 ×15÷100 = 94,500

II year interest = $420,000×15÷100 = 63,000

III year interest = $210 ,000×15÷100 = 31,500

Total interest = 94,500+63,000+31,500 = 189.000

Installments payment with interest for each year is=
(630,000 + 189,000 = 819,000÷ 3 = 273,000)

= $273 ,000 being the equal installments for all the three years