Word problem using elimination

Question

Thomas has $6000 invested among a checking account paying 2% annual interest, a savings

account paying 5% annual interest and a bond paying 7% annual interest. He earns a total of

$355 in annual interest and he has $2300 less invested in his savings account than in his bond.

How much has he invested in each account?

Answer 1

C + S + B = 6000 = Total deposit

c+ s + b= 355 ( Total interest )

Int = Prt

c = C*2*1

s = S* 5*1

b = B*7*1

Also C + B - 2300 +B = 6000

C+2B = 8300

Also

2C +5S +7B =355

From above equations find C, S and B