[ 2360 - ( 250 + 25 × a ) : 2 ] : 5 = 419
2360 - ( 250 + 25 × a ) : 2 = 419 × 5
2360 - ( 250 + 25 × a ) : 2 = 2095
( 250 + 25 × a ) : 2 = 2360 - 2095
( 250 + 25 × a ) : 2 = 265
250 + 25 × a = 265 × 2
250 + 25 × a = 530
25 × a = 530 - 250
25 × a = 280
a = 280 : 25
a = 11, 2
