No, Shayna is not correct. Here's the calculation:
Initial pressure (P1) = Force (F1) / Area (A1)
P1 = 60 N / 10 cm² = 6 N/cm²
Increased force (F2) = 60 N + 15 N = 75 N
Increased area (A2) = 10 cm² + 15 cm² = 25 cm²
New pressure (P2) = Force (F2) / Area (A2)
P2 = 75 N / 25 cm² = 3 N/cm²
Percentage decrease in pressure = ((P1 - P2) / P1) * 100
Percentage decrease = ((6 N/cm² - 3 N/cm²) / 6 N/cm²) * 100 = 50%
The pressure decreases by 50%, not more than 40%.