Answer:
The width and height is 1.375 and 4.375 respectively
Explanation:
The computation of the width and height of the book case is shown below:
Let the width be w
And, the height be h
So, the following equations should be made
5w+3h=20 ......(i)
h = w + 3......(2)
Now
put the value of h in equation (1)
5w + 3(w + 3) = 20
5w + 3w + 9 = 20
8w = 20-9
8w = 11
w = 11 ÷ 8
= 1.375
And, the height would be
= 1.375 + 3
= 4.375