The Question

HSAs Method

BLYs Method

ACHs Method

The Question:

BLYs Method

HSAs Method

SMAs Method

Would have done it similarly but without introducing the variable B, so all in terms of R

R : 4R

R+7 : 3(R+7)

We know the Bs were unchanged so

4R = 3(R+7)

Giving us R=21

And then B is 3(21+7)=84