Yes, the 36" shelf can hold all 24 books. As 5/4=1.25" meaning, you take 1.25X24=30". So 24 books only take up 30 inches of a 36 inch shelf.
Tanθ = 8.9352
θ = tan⁻¹ (8.9352)
<span>θ </span>≈<span> 83.614</span>°
So if the ratio is 2:3, then the younger child would represent the 2. so it would be 2:3 is 4:x. Thereby, the answer would be 6, because of proportions. To check, simplify 4:6, and you would get 2:3.