10 people meet, and each person shakes every other person's hand once. how many handshakes occurred?

45 handshakes

Step-by-step explanation:

If there are n persons and each person shakes every other person hand once then the total number of handshakes are

Now, it has been given that 10 people meet, and each person shakes every other person's hand once.

Therefore, n = 10.

Hence, from the above mentioned formula, we have

Total number of handshakes =

Hence, total 45 handshakes were occurred.

since the airplane is moving with constant speed then the distance travelled can be calculated by x=u*t

in km/h would be:

x=640*3.5=2.240 km

in m/s would be:

u=640 km/h= 640.000 m/h =640.000/ 3600 m/s =177.8 m/s

t= 3.5 h= 3.5 * 3600 s=12.600 s

then x=u*t= 177.8*12.600= 2.240.280 m

typically if you want , you would actually put questions here for us to you. but hey, that's just me. maybe someone will magically answer the questions for you without knowing what they are.