Physics ramp/acceleration problem

[scorks]

Block A has a mass of 5.26 kg and is on a rough incline of 16.0°to the horizontal. Block B has a mass of 4.80 kg and the coefficient of kinetic friction between Block A and the plane is 0.204. What is the acceleration of the blocks?

Equations= fnet=ma

Attempt:(4.8+5.26)a=(4.8)g-(5.26)gsin(16°)-(μ)(9.8)(5.26)(cos(16°))
Therefore a=3.00m/s^2
This comes out to be the wrong answer, according to the key. Help?!

 

[Eango]

I get 1.7 m/s^2. Tell me if that's right and i will explain.
i think you went wrong on the friction bit. Friction = UN and force N=FG. You didn't add all your masses for some reason on the friction part.

 

[scorks]

I get 1.7 m/s^2. Tell me if that's right and i will explain.
i think you went wrong on the friction bit. Friction = UN and force N=FG. You didn't add all your masses for some reason on the friction part.

Nope, unfortunately they say that's wrong D:

 

[Eango]

I see what i did XD
Lets see... (If this isn't right, ill shoot myself...JK)Sum of F = ma
Fg - Ff = ma
mg - UN = ma
m1+m2gsin(16) - U X m1+m2cos(16)=m1+m2(a)
a= m1+m2gsin(16) - Ux m1+m2cos(16)/ m1+m2
a= 5.26+4.8sin(16) - 0.204 X 5.26+2.8cos(16)/ 5.26+2.8
a=-1.84

 

[Eango]

a = -1.84 m/s^2 :P