= ( 60 + 50+40+30+20+10 ) x 2000 + 1500
= 210 x 2000 + 1500
= 420000 + 1500
= 421500
(60 + 40 ) + (50 + 30 + 20 + 10) x50 x 40 + 50 x30
( 60 + 50 + 40 + 30 + 20 + 10 ) x 50 x 40 + 50 x 30 = 421500
(60 + 50 + 40 + 30 + 20 + 10) x 50 x 40 + 50 x 30 = 630000000
= 6.3*10^8