Answer:
V=4/3πr^3;S=4πr^10;dV/dt=dV/dr×dr/dt=4πr^10×dr/dt;dS/dt=dS/dr×dr/dt=8πr×dr/dt=2/r×dV/dt;当r=10cm时,dS/dt=50cm^2/s
Step-by-step explanation:
Answer:
There would be 18 boys.
Step-by-step explanation:
If the ratio of boys to girls is 3:4 that means in a classroom of 7 people there would be 3 boys and 4 girls. So all you do is multiply 3 boys by 6 (18) and 4 girls by 6 (24) cuz 7*6=42 which means that there would be a total of 42 students with 18 boys and 24 girls.