So since z=5 you are going to substitute z in the equation with 5. So it should look like 0.3y+y/5 = 10. So in this problem I assume you are solving for y so you will divide on both sides of the equation. So 0.3y/ 0.3 cancels out and you are left with y/5=10/0.3 so 10/ 0.3 is 33.3333333333. Now you are left with y/5=33.3333333333 . Now didvide 5 on both sides. Y should equal 6.66666666667. This was tricky. Hoped that helped !!!
The idea is to find the value of y with z=5. To do this, it is necessary to replace the value of z in the left part of the equation and then find the y value.
First step
When we replace the z value we obtain the term which equals . Then, equals 0.2.
Second step
We must add the terms with the y letter. They are 0.3y and 0.2y
Third step
The last step is to pass the 0.5 to divide with 10. It would be:
I think the answer is A because the balance after 4 years is not on their and so we are trying to find the balance after three years. And after 3 years the balance is 805