System of equations, please help.

3.75*A + 2.50*D = 35

A + D = 12

A = 12 - D

3.75*(12-D) +2.5*D= 35

45 - 3.75D + 2.5D = 35

45 - 1.25D = 35 |-35

10 - 1.25D = 0 |+1.25D

10 = 1.25D | /1.25

8 = D

A+D=12

A+8=12 |-8

A=4

If you like it, brainliest would be cool

a)

$4,000 + $960 = $4,960

She has $4,960 in her account at the end of 3 years

b)

i = Prt

r = i/Pt

r = 960 / 4000 * 3

r = 960 / 12000

r = 0.08

Annual interest rate is 0.08 or 8%

c) If 1% greater then r = 0.09 (9%)

i = Prt

i = $4,000 * 0.09 * 3

i = $1, 080

The different: $1, 080 - $960 = $120

She would have $120 more in her account if the interest rate were 1% greater.