At M = +2.5P
$M_c = \dfrac{10(192)(1000)}{2.5} \,\, \to \,\,$ upper fiber
$2.5P = 768\,000 \, \text{lb}\cdot\text{in}$
$2.5P = 64\,000 \, \text{lb}\cdot\text{ft}$
$P = 25\,600 \, \text{lb}$
$M_t = \dfrac{4(192)(1000)}{4} \,\, \to \,\,$ lower fiber
$2.5P = 192\,000 \, \text{lb}\cdot\text{in}$
$2.5P = 16\,000 \, \text{lb}\cdot\text{ft}$
$P = 6400 \, \text{lb}$
At M = -5.0P lb·ft
$M_c = \dfrac{10(192)(1000)}{4} \,\, \to \,\,$ lower fiber
$5.0P = 480\,000 \, \text{lb}\cdot\text{in}$
$5.0P = 40\,000 \, \text{lb}\cdot\text{ft}$
$P = 8000 \, \text{lb}$
$M_t = \dfrac{4(192)(1000)}{2.5} \,\, \to \,\,$ upper fiber
$5.0P = 307 200 \, \text{lb}\cdot\text{in}$
$5.0P = 25 600 \, \text{lb}\cdot\text{ft}$
$P = 5120 \, \text{lb}$
Use P = 5 120 lb answer
